Randomly one day my thunderbird says "Login to server pop.centurylink.net with username vxxxxxxx@gulftel.com failed." My user and password are correct as is my server settings. I contacted centurylink and they told me its on mozillas end and unfortunately mozilla doesnt have a customer service number. I've tried deleting and redownloading Thunderbird, deleting the account and readding it and it still wont let me access it.