Users at one site all report that they are not receiving email, and they receive a timeout trying to send email. Their internet connection is fine. I am able to install Thunderbird on a server at their location, set up an account and read and send email. All of the workstation email accounts simultaneously stopped working. I can remotely control some of these machines, and on the one I tried, they were not asked for a password when they started thunderbird (they normally are asked). I verified that the server settings are correct for the machine I connected to, though that was not a promising approach as all workstations stopped working simultaneously. I have no idea where to look. Any suggestions?