You need to provide information regarding the issue. What OS are you using? What version of Thunderbird are you using? Is this an imap or pop mail account ? It seems you are getting an error - please tell us what the error says exactly word for word or upload an image. Tell us what you see in this location: In Thunderbird * Help > Troubleshooting Information * Scroll down to 'Mail and News Accounts' section * Copy all the information in that section and paste it into this forum question OR upload an image showing all the data. This will tell us what server you are using, so we can check all is correct. Please do the following: Logon to your webmail account using a browser. If you can logon then we know the password you are using is correct. Please confirm you can logon to webmail account. Please keep all further communication in this forum question.