When you logon to your webmail account via a browser, you will always be asked for username = email address and a password. Every email account on every server requires a password to access it. When Thunderbird needs to access that server account to download or send emails it needs to know that password. It sounds like you set up the pop account some time ago and told Thunderbird to remember the password. So, it's been using that password and getting on with retrieving emails to display in pop account. You will not get rid of a request for password until you have entered the correct password. In Thunderbird, stored passwords are here: * Settings > Privacy & Security * Scroll to Passwords section * Click on 'Saved Passwords' * click on 'Show Passwords' At this point you may get asked for a password. Less likey - If in the past you set up a 'Primary Password' in Thunderbird then the checkbox 'Use a Primary Password' will be selected and this is the password you enter at the prompt - it has nothing to do with mail accounts. If using Windows OS: When you start up computer and you enter a password to logon to see desktop etc - that is the password you enter at the prompt. Now you can see stored passwords. Do you see the pop account in the stored list ? It will have two lines - incoming starts with 'mailbox://account.... and outgoing starts with smtp://accounts.... Both should have username as full email address and display the password whic in most cases is identical. If you see that password then try to use it to logon to your webmail account via a browser. If you cannot get access to webmail account because password does not work or no password stored then use the 'Forgotten Password' link which is usually provided and follow instructions to get access to webmail account. Then reset the password. Please log out of webmail and try to logon again using new password to ensure it works. Then in Thunderbird if no password stored: Enter password at prompt and select the checkbox to remember password before you click on OK OR if update the stored password in Thunderbird * Right click on the mailbox://account...line and select 'Edit Password' * Completely clear contents and then type in the new and correct password. * REpeat for the smtp://account line. * Click on 'Close' Exit Thunderbird and wait a few moments for background process to update files. Then restart Thunderbird. It would help if you always supplied the following when asking a question: What OS you are using? What version of Thunderbird are you using? You mentioned Pop but it's a good idea to state what server you are using because sometimes server's change what they require. In Thunderbird it helps to post the following: * In Help > Troubleshooting Information * scroll down to 'Mail and News Accounts' section * Copy all the data and post info in this question OR upload an image showing data.