User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Firefox/31.0 (Beta/Release) Build ID: 20140716183446 Steps to reproduce: I updated TB to version 31.0. Actual results: After the upadate, several e-mail accounts by Domainfactory.de and netbeat.de cannot send e-mails anymore. The netbeat.de account still allows sending e-mails but not receiving. Web.de and yahoo.com e-mail accounts are not affected, they still allow sending and receiving. Checking all settings over and over again made sure that everything is as it should be (passwords, port and server settings etc.) Also installing the SSL certificates did not help. Removing the profile and de-installing TB totally and re-installing evertyhing anew did not solve the problem. Expected results: Receiving and sending of e-mails by the e-mail providers of Domainfactory.de and netbeat.de should work properly.