How to fix Thunderbird error 10061 (connection refused)
This means the server actively refused the connection, which almost always points at a wrong port number, server address or security setting. Jump to your situation below or work through the methods in order.
By Neeraj Singh ~5 min Updated Jun 2026 89% found this helpful
Error message
Connection refused (error 10061). The server actively rejected the connection attempt.
Summary
Error 10061 means the connection was actively refused: unlike a timeout, the server (or a device in front of it) received the request and immediately said no. The cause is nearly always a wrong port number, a wrong server hostname, or a connection-security setting that does not match the port. If Thunderbird tries the wrong port, nothing is listening there and the connection is refused. The fix is to set the correct, current values from your provider: IMAP 993 or POP 995 for incoming, and SMTP 587 (STARTTLS) or 465 (SSL/TLS) for outgoing, with the matching connection security. Confirming the exact server hostnames and ruling out a firewall that refuses the port resolves the rest. Because it is a refusal rather than a hang, 10061 is usually a quick settings fix.
What this error means
A refused connection is the opposite of a timeout. Instead of going out and never returning, the request reaches its destination and is immediately rejected, because nothing is listening on that port or a device is configured to refuse it. That is a fast, definite no.
For mail, that almost always means Thunderbird is pointed at the wrong port, or at a port that does not match the chosen security (for example plain on a port that only accepts SSL). Setting the correct port, hostname and security for your provider lines everything up and the connection is accepted.
Common causes
The incoming or outgoing port number is wrong.
The server hostname is wrong.
The connection security does not match the port.
A firewall is configured to refuse the port.
The provider changed its server settings.
Expert insight
“Refused is a much friendlier error than timed out, because it usually means a simple settings mistake. The server is there, it just said nothing is listening on that port. So I go straight to the ports: 993 for IMAP, 995 for POP, and 587 or 465 for SMTP, and I make sure the security matches, SSL on 993 and 465, STARTTLS on 587. Line those up with the right server name and the refusal turns into a clean connection.”
Manager, Tech Support & Operations · 19+ years fixing Windows and system errors
✓ How to fix it
Method 1
Set the correct ports
1Set incoming to IMAP 993 or POP 995, and outgoing to SMTP 587 or 465.
2These are the standard secure ports.
3A wrong port is the most common cause of a refusal.
Method 2
Verify the server hostnames
1Check the incoming and outgoing server names against your provider's documentation, for example imap.example.com and smtp.example.com.
2Correct any typo or outdated value.
3Providers occasionally change these.
Method 3
Match the connection security
1Set Connection security to SSL/TLS for ports 993, 995 and 465, and STARTTLS for port 587.
2A mismatch between port and security causes a refusal.
3Save and retry.
Method 4
Rule out a firewall
1Make sure a firewall or antivirus is not configured to refuse the mail ports.
2Allow Thunderbird and the ports through.
3Then test.
Method 5
Test the connection
1Send and receive a test message to confirm the server now accepts the connection.
2If it changes to a timeout (10060), a firewall or antivirus is now the issue.
10061 is an active refusal, so it is almost always a wrong port, hostname or security setting rather than a network fault. Set the standard secure ports, IMAP 993, POP 995, SMTP 587 or 465, and match the connection security to each. Confirm the exact server names from your provider, since these are occasionally changed.
Frequently asked questions
What does Thunderbird error 10061 mean?
It means the connection was actively refused: the server or a device in front of it received the request and immediately rejected it, almost always because of a wrong port, hostname or security setting.
How do I fix connection refused in Thunderbird?
Set the correct ports (IMAP 993, POP 995, SMTP 587 or 465), verify the server hostnames against your provider, and match the connection security (SSL/TLS or STARTTLS) to each port.
Which ports should I use?
IMAP 993 and POP 995 for incoming, SMTP 587 (STARTTLS) or 465 (SSL/TLS) for outgoing. These are the standard secure ports most providers use.
How is 10061 different from 10060?
10061 is connection refused, an immediate rejection usually from a wrong port or address. 10060 is connection timed out, the server never replied, usually a firewall or antivirus.
Why does the security setting matter?
Each port expects a specific security type. Using plain or the wrong security on an SSL-only port causes the server to refuse the connection. Match SSL/TLS or STARTTLS to the port.
Could the provider have changed settings?
Yes. Providers occasionally update server names or ports. Re-check the current incoming and outgoing settings in your provider's documentation and update Thunderbird to match.
Still not working?
If the ports, hostnames and security are all correct and the connection is still refused, a firewall, antivirus or network is refusing the port before it reaches the server. Test on a different network and with security software paused to confirm, then add the needed exception. You can also submit your error to us for a tailored fix.
