How to fix “your calendar couldn't be refreshed” and “the server responded with an error”
Your Mac, iPhone or iPad is telling you Apple Calendar could not fetch new data, and the alert itself already says why. Find your situation below, most people are fixed in a few minutes.
By Neeraj Singh ~14 min Updated Jul 2026 90% found this helpful
Error message
Your calendar couldn't be refreshed. | Access to account “…” is not permitted. | The request for account “…” failed. The server responded with “403” to operation CalDAVAccountRefreshQueueableOperation.
Quick fix
Seeing “Access to account is not permitted” or a “403”? Take a breath, nothing is broken and your events are safe. Your device has simply lost its saved sign-in for that account and needs you to log in again. Turn Calendars off for the account named in the popup (Mac: System Settings > Internet Accounts, iPhone: Settings > Apps > Calendar > Calendar Accounts), restart, turn it back on and sign in when asked. Still popping up? Remove the account and add it back, Method 2 walks you through it.
Popup shows a “404”, or it keeps coming back no matter what you do? The calendar your device keeps asking for no longer exists at that address. Delete the old account or subscription and add it back with the provider's current link, Method 3 and Method 5 show you exactly where to click.
A “502” or “504”? This one is not you at all, the provider's server is having a bad day. Wait a while and try again, there is nothing on your device to fix.
Using a subscribed calendar link? Do a one minute check: change webcal:// to https:// in the link and open it in your browser. A calendar file downloads? Then your device is the culprit, Method 7 clears it. The browser shows an error? The link itself is dead, Method 5 gets you a fresh one.
What the refresh error means in Apple Calendar
Your first job takes ten seconds: spot which kind of calendar is failing for you, because the fix is different for each. Apple Calendar shows events from more than one kind of source. A subscribed calendar is a read-only feed: the app periodically downloads an .ics file from a fixed URL, often added through a webcal:// link. An internet account is a two-way sync with a server such as iCloud, Google, Exchange, Yahoo or any CalDAV service, signed in through Internet Accounts. A refresh failure means one of those fetches did not complete, so the calendar stops syncing new events, and the alert appears as a dialog or as a warning triangle next to the source in the sidebar.
Apple's own guidance for that warning symbol is that Calendar could not connect to the calendar account: check the connection, refresh again and confirm the calendar has not been deleted or moved. Calendars do get moved, providers do retire old sync addresses and sign-ins do expire, and each of those produces this same generic headline with a different number underneath.
Figure 1: the same alert covers two different sources
Read the alert before you fix anything
Your full alert follows a pattern: The request for account “X” failed. The server responded with “N” to operation SomeLongOperationName. Two parts of that are useful and one is noise. The account name tells you which of your sources broke. The number is an HTTP status code straight from the calendar server, and it picks your fix for you. The operation name, such as CalDAVAccountRefreshQueueableOperation or CalDAVRefreshDelegateListQueueableOperation, is only Apple's internal label for the background task that was running. Ignore it.
Figure 2: what the number in the alert points at
Common causes of a failed calendar refresh
The account's stored sign-in or OAuth token expired or was revoked (403, very common with Google).
A stale account entry points at a sync address the provider retired, so every refresh returns 404.
The subscription URL is wrong, changed or the publisher deleted or moved the calendar.
The provider's server is down or timing out (502, 504), which no device setting can fix.
An SSL certificate on the calendar host cannot be verified, so the connection is refused.
Corrupt Calendar cache files on a Mac keep a broken sync state alive across restarts.
There is no network, or a VPN, proxy or firewall blocks the calendar host.
Expert insight
“The wording sounds like your device is broken, but the alert itself already did the diagnosis for you. If it says access to an account is not permitted, I do not touch the URL at all, that is a sign-in problem and re-authenticating the account fixes it nine times out of ten. If it is a subscribed feed, I take the URL, change webcal to https and paste it into a browser. A clean .ics download means the source is fine and I look at the device. A browser error means the URL or the provider is at fault, and no amount of fiddling on the device will fix that.”
Manager, Tech Support & Operations · 19+ years fixing Windows and system errors
✓ How to fix it
Work through these in order, or jump straight to the method your alert points at. Each one tells you what you should see once it has worked, so you always know whether to stop or keep going.
Method 1
Refresh manually and read the full alert
1On a Mac, open Calendar and choose View > Refresh Calendars. On an iPhone or iPad, open the Calendar app, tap Calendars and pull the list down to force a refresh.
2If a warning triangle sits next to a calendar in the sidebar, click it to see the complete message with the account name and the HTTP code.
3For a subscribed calendar, Control-click its name and choose Get Info to see the exact web address Calendar is fetching. You will need it in Method 4.
Method 2
Re-authenticate the account (403, access not permitted)
1On a Mac, open System Settings > Internet Accounts and select the account named in the alert. On an iPhone, go to Settings > Apps > Calendar > Calendar Accounts.
2Turn the Calendars switch off for that account, restart the device, then turn it back on. Server-synced events return once the account reconnects, only the local copy is cleared.
3If the alert comes back, remove the account entirely and add it again, completing the full sign-in and any two-factor prompt. For Google this issues a fresh OAuth token, which is exactly what a 403 is asking for. You will know it worked when the warning triangle disappears and your events fill back in within a minute or two. If the failing account is iCloud and the sign-in itself fails with a verification alert, clear that first with the iCloud verification failed guide.
4If you changed the provider password recently, the device is still sending the old one, so update it when prompted. A CalDAV account added manually for Yahoo or AOL needs an app password generated on the provider's account security page, the normal account password is refused there.
5A Google account that still returns 403 after a full re-add can have a stale permission grant on Google's side. Open your Google Account's security settings, remove the old Apple or macOS entry under third-party connections, then add the account once more so a fresh grant is created.
Method 3
Remove stale or duplicate account entries (404, repeating alerts)
1An alert that pops up endlessly usually comes from an old account Calendar still tries to sync in the background, and unchecking its calendars does not stop that.
2Look through Internet Accounts for duplicates or accounts you no longer use, especially Google accounts added years ago. Old entries can point at sync addresses the provider has since retired, which is where a persistent 404 comes from.
3Delete the dead entry. If you still need that calendar, re-add the account fresh so it is configured with the provider's current sync address. The moment the stale entry is gone, the endless popup stops.
Method 4
Test the subscription URL in a browser
1Take the URL from Get Info, replace webcal:// with https:// and open it in a browser.
2If a valid .ics downloads, the source is healthy and the fault is local: re-add the subscription (Method 5) or clear the cache (Method 7). If the browser errors, the URL or provider is the problem and the device is fine.
3If the file downloads but will not open or import cleanly, the source .ics itself is malformed: follow the parse error guide or ask the publisher to fix their feed.
Figure 3: the one-minute browser test and where each result sends you
Method 5
Re-add the subscription with the current URL
1Providers change feed URLs, and a subscription keeps polling the address it was created with. Get the current link from the provider's site, not from an old email.
2Unsubscribe from the broken calendar: on a Mac, Control-click it in the sidebar and choose Unsubscribe.
3Subscribe again with the fresh URL: on a Mac via File > New Calendar Subscription, on an iPhone via Settings > Apps > Calendar > Calendar Accounts > Add Account > Other > Add Subscribed Calendar. The feed's events should appear as soon as the first refresh runs, that is your confirmation.
Method 6
Fix a certificate problem
1If the browser test in Method 4 shows a certificate warning instead of downloading the file, the connection to the calendar host cannot be verified.
2Work through the cURL error 60 guide, which covers an expired certificate, a broken chain and a wrong device clock.
3Retry the refresh once the URL loads in a browser without any warning.
Method 7
Clear the Calendar cache on a Mac
1Back up first: in Calendar choose File > Export > Calendar Archive. Then quit Calendar, open Activity Monitor and quit the CalendarAgent process so the cache is not in use.
2In Finder choose Go, hold the Option key and click Library, then open the Calendars folder. Move every file with Calendar Cache in its name to the Desktop.
3Reopen Calendar and give it a minute. It rebuilds the cache from your accounts, which clears a corrupt sync state that survives restarts and account toggles. When your calendars repopulate without the alert, you are done, delete the moved files.
Method 8
Check the refresh settings and the connection
1A subscribed calendar refreshes on its own schedule: Control-click it, choose Get Info and set Auto-refresh. Every hour is a sensible choice, and an interval of every 5 minutes is rarely worth the battery and server load.
2Account calendars refresh per the setting in Calendar > Settings > Accounts > Refresh Calendars, where Push updates as changes happen. On an iPhone the equivalent is the account's Fetch New Data schedule.
3Confirm the device is online, and briefly disable any VPN, proxy or filtering software to rule out a blocked calendar host. Retry on another network if the alert persists.
Method 9
Update macOS and test in Safe Mode
1Install any pending update via System Settings > General > Software Update. Calendar account bugs do ship with new macOS versions and get fixed in point releases, so an out of date or freshly updated system is a real suspect.
2Restart in Safe Mode and open Calendar. If the error is gone there, a login item or cached system state is interfering, so clear the Calendar cache (Method 7) and review recently added startup software, then restart normally and retry.
Match the fix to the code: a 403 is never fixed by changing a URL, and a 504 is never fixed by signing in again. If the alert shows no code at all, start with the browser test in Method 4.
Make sure this is the error you have
A few nearby problems look similar and have their own guides. A close sibling is “Your event couldn't be refreshed. The calendar was not found on the server”, which is event level rather than calendar level: a Google or Workspace invite was added locally but never accepted on Google's side, often because Google held back an invite from an unknown sender, so open the invite in Google Calendar on the web and accept it there. If an .ics file downloads but Outlook or another app cannot read it and reports 0x804A0105 or ICAL_PARSE_ERROR, the file itself is broken: use the parse error guide. If the failure is an SSL verification message, that is cURL error 60 territory. And if a calendar simply lags rather than erroring, that can be normal: Apple refreshes a subscribed feed on whatever Auto-refresh interval is set for it, while Google Calendar refreshes a subscribed URL on its own schedule, often taking up to a day, with no user control, so a slow update in Google Calendar is not this error at all. And if the failing source is iCloud and you also see numbered errors between 3000 and 3999, work through the iCloud sync errors guide instead.
Frequently asked questions
Why won't my calendar refresh in Apple Calendar?
Calendar could not fetch new data from one of its sources, either a subscribed .ics URL or an internet account such as iCloud, Google, Exchange or Yahoo. The alert usually names the account and carries an HTTP code such as 403, 404 or 504 that tells you whether the problem is sign-in, a dead URL or the provider's server.
What does access to account is not permitted mean?
The calendar server refused your credentials, which is why it usually arrives with a 403. The stored sign-in or token for that account has expired or been revoked. Toggle Calendar off for the account in Internet Accounts, restart, toggle it back on and complete the sign-in. If the alert returns, remove the account and add it again.
What is CalDAVAccountRefreshQueueableOperation?
It is the internal name of the sync task Apple Calendar was running when the request failed. Operation names like this only identify which background job hit the wall. The useful part of the alert is the number next to it, such as 403 or 504.
What do the numbers like 403, 404 and 504 mean?
They are HTTP status codes from the calendar server. 403 means permission was refused, so fix the sign-in. 404 means the calendar address no longer exists, so the URL or account configuration is stale. 502 and 504 mean the provider's server is failing or timing out, which only the provider can fix.
How do I test a subscription URL?
Replace webcal:// with https:// and open the address in a browser. If a valid .ics file downloads, the source is healthy and the fault is on your device. If the browser shows an error, the URL or the provider is the problem and nothing on the device will fix it.
How do I stop the alert popping up over and over?
A repeating alert usually comes from a stale account that Calendar still tries to sync, often an old Google entry left in Internet Accounts. Unchecking its calendars is not enough. Remove the dead account entirely, then re-add it fresh if you still need it.
How often does Apple Calendar refresh a subscribed calendar?
There is no single interval. Each subscribed calendar follows its own Auto-refresh setting: Control-click it, choose Get Info and pick anything from every 5 minutes to weekly. Account calendars follow the Refresh Calendars setting under Calendar > Settings > Accounts, where Push updates as changes happen.
Why does the calendar work on my iPhone but not my Mac?
Each device stores its own copy of the account credentials and its own cache. An expired token or a corrupt Calendar cache on the Mac breaks only the Mac. Re-authenticate the account on the failing device, and on a Mac clear the Calendar cache files if sign-in alone does not help.
Will removing the account delete my events?
Events that live in a server account such as iCloud, Google or Exchange stay on the server and come back when you re-add the account. Only calendars stored locally under On My Mac live on the device alone. To be safe on a Mac, back up first with File > Export > Calendar Archive.
Is this a problem with my device?
Not always. A 403 or a corrupt cache is on your side, while a 404, 502 or 504 points at the URL or the provider. Test the subscription URL in a browser or check the provider's status page before changing anything on the device.
Still not working?
If the browser test downloads a clean .ics but the calendar still will not refresh on the device, remove the subscription, restart the device and re-add it, which clears a stuck sync state. For an account calendar that keeps failing after a full remove and re-add, test in a new user profile on the Mac to separate a profile problem from an account problem, and check whether the same account works in the provider's own web calendar. Browse the full set of iCalendar and ICS error guides for anything adjacent, submit your error to us for a tailored fix.
