We'll need some more information. Could you please do the following? # Open the menu '''[[Image:Fx57Menu]] > Help > Troubleshooting Information''', then click '''Copy text to Clipboard'''. # Go to https://pastebin.com, paste the info from your Troubleshooting Information page, use the '''Create New Paste''' button to create a page containing your info, then copy the resulting URL (address) of the page created. # Open a reply to this post, and paste the link to your troubleshooting information you just copied. Next, we'll need you to provide answers to the following questions: * Does Thunderbird work in [[Safe Mode Thunderbird|Safe Mode]]? * Do you use anti-virus and firewall software? What is the version? * 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? * Did you see any error messages