this is usually caused by incorrect settings in the server set up. You will need to check with your email provider's page to make sure everything if correct, including server address, port numbers and encryption types.

Already checked all that with the provider and everything is correct.

Hi. We noticed that the troubleshooting information was missing from these questions. In order to better investigate this issue, we may need to request a little more non-personal information.

Please add the troubleshooting information to your post as well as the results of the following troubleshooting steps:

• Finding the Troubleshooting information
• Does Thunderbird work in TB Safe mode (see Thunderbird Safe Mode)?
• What is the Thunderbird version?
• What operating system do you use (e.g. Windows 7)?
• Do you use anti-virus and firewall software? What is the version?
• Do you use Thunderbird add-ons?
• Who is the email provider?
• Who is the internet provider?
• What is the exact error message?
• What steps did you take right before this happened?

With this information we can better investigate and get a better idea of what may be causing the issue.

Please post back with this information and any other questions you might have.