<blockquote> now it is asked for master password for zoho.com. </blockquote> Please post a screenshot of the error message. https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem Did you set a master password in the first place? http://kb.mozillazine.org/Master_password <blockquote> Is that unrelated to logging in to thunderbird? </blockquote> You do not login to Thunderbird. You do login to your account on the server using Thunderbird. <blockquote> Option for new password is not working. </blockquote> Please explain what that means. You can verify your password by logging in to your acccount via webmail.