How to fix connection to server timeout error in Thunderbird?

Symptom

When you attempt to send and receive e-mail, or attempt to send and receive a large message, Thunderbird error message;

Connection Timed Out

Cause

This error message may occur if Mozilla Thunderbird closes the active connection before you have fully downloaded all your email messages.

If you’re sending an e-mail with a large attachment, you may also see this error. This is because the file size of the attachment in the e-mail message is too large, the e-mail message cannot be sent within the time limit.

Resolution

Increase the server timeout setting in Mozzila Thunderbird.

How to increase server timeout in Thunderbird Version 2.x on Microsoft Windows

  1. Open Thunderbird
  2. From the Tools menu, click Options
  3. Click Advanced
  4. Click Network & Disk Space
  5. Increase Connection timeout from 60 to 120
  6. If problem persists, increase timeout.

How to increase server timeout in Thunderbird Version 2.x on Mac OSX

  1. Open Thunderbird
  2. From the Thunderbird’s menu, click Preferences
  3. Click Advanced
  4. Click Network & Disk Space
  5. Increase Connection timeout from 60 to 120
  6. If problem persists, increase timeout.