Padlocks are not a problem They simply indicate accounts which use a secured connection, and an encryption technology such as SSL or TLS. Here are my accounts. All of them work. The few without padlocks are genuinely non-secured. Maybe if you post your settings we can go forward to solve your connection problems. Please add the troubleshooting information to your post. To find the Troubleshooting information: # Open ''Help'' (or click on three-line-icon and select ''Help''); # Choose ''Troubleshooting Information''; # Clear the check box ''Include account names''; # Use the button ''Copy to clipboard'' to select all; # Paste this in your post. Please also add the result of these troubleshooting steps to your post *Does Thunderbird work in TB Safe mode (see [http://mzl.la/1k5DWjq 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? *Is there any error message? What is the exact error message? *What steps did you take right before this happened? Please post back with this information and any other questions you might have.