But even a reliable email service such as Thunderbird may stop working from time to time.
The SMTP server (Simple Mail Transfer Protocol) plays the role of the mailman in the email world.
In other words, the emails you send are first collected by the SMTP server.
The server then distributes them to the recipients.
Not using the correct SMTP prefs may prevent you from sending emails using Thunderbird.
Thats why it’s crucial that you ensure youre using the correct SMTP server tweaks.
Ensure youre not trying to send emails from Thunderbird using the SMTP server of another email service.
Or they could be blocking the emails coming to your inbox.
To test if your antivirus or firewall is blocking outgoing emails, simply deactivate the tools.
For detailed instructions, go to your antivirus/firewall official support page.
If this problem occurred shortly after you updated Thunderbird, whitelisting the email tool should fix it.
Your antivirus/firewall may not trust the new Thunderbird version.
Thats why it’s crucial that you get your security programs to recognize and trust the updated Thunderbird version.
If youre using a security tool from ESET, try turning off SSL filtering.
Use this method if you cant receive emails on Thunderbird.
Rollback Thunderbird
Thunderbird 78 and higher require enhanced TLS security standards.
As a workaround, you’ve got the option to rollback Thunderbird.
you could find the list of previous Thunderbird versions onMozillas support page.
Switch to another port or contact your ISP for further help if you still cant send emails.
If you have problems receiving emails, find out if everything is up and running on your ISPs end.
Contact your ISP and test whether they set up a spam filter.
