How to Fix unable to send Email Messages in Thunderbird?

Steps to Fix Unable Send Email Messages in Thunderbird :

If you are unable to send email messages from your Thunderbird account, there can be two reasons behind this:

  • Inappropriate Thunderbird Settings
  • Blocked Port 25 by ISP (Internet Service Provider)

Solution – To resolve this error in Mozilla Thunderbird, perform the following:

Step 1: Ensure that Thunderbird settings are appropriately configured:

  • Incoming mail server (POP3/IMAP server):
  • Outgoing mail server (SMTP server):
  • Username: the full e-mail address like [email protected]
  • SMTP authentication must be enabled for the login to be successful.

Step 2: Try using alternative TCP port 2525 for SMTP Server.