This means Thunderbird reached out to the mail server but got no reply in time. A firewall or antivirus blocking Thunderbird is the usual cause, along with a wrong server or port. Jump to your situation below or work through the methods in order.
Error 10060 is a network timeout: Thunderbird tried to connect to the incoming or outgoing mail server and received no response within the allowed time. The most common cause is a firewall or antivirus blocking Thunderbird, especially security suites with an email-scanning feature that sits between Thunderbird and the server. A wrong server name or port, or a general connectivity problem, produce the same timeout. The fix is to confirm the internet connection works, then make sure Thunderbird is allowed through the Windows firewall and any third-party antivirus, disabling email or SSL scanning in the antivirus if present. Verifying the server hostname and port against your provider's settings, and testing on a different network or with a VPN off, clears the remaining causes. If the connection is simply slow rather than blocked, raising the connection timeout helps.
A timeout means Thunderbird sent a connection request and simply never heard back in time. That is different from being actively refused, the request goes out and vanishes, which points at something silently dropping the traffic rather than a wrong setting alone.
That silent drop is usually a firewall or antivirus. Many security suites scan email by intercepting the connection, and if that scanning misbehaves or blocks Thunderbird, the connection hangs and times out. A wrong server or port, or a flaky network, cause the same symptom, so those are the things to check.
“A timeout is the connection going out and never coming back, which almost always means something is quietly eating it, and that something is usually antivirus or a firewall. The big security suites love to scan email by sitting in the middle of the connection, and when that goes wrong Thunderbird just hangs until it times out with 10060. I let Thunderbird through the firewall, turn off the antivirus email scanning, and confirm the server and port are right, and the connection springs back to life.”
A 10060 timeout is the connection being silently dropped, so the prime suspects are a firewall or antivirus, not a typo in your settings. Allow Thunderbird through the firewall and turn off antivirus email or SSL scanning first. If the connection is merely slow rather than blocked, raising the response timeout, covered in our server-timeout guide, can help.
If the firewall and antivirus are cleared and the server settings are correct but 10060 persists, the connection may simply be too slow for the default timeout. Raise the mailnews.tcptimeout value in the Config Editor, as described in our server-response-timeout guide, then retry. You can also submit your error to us for a tailored fix.
