We have not changed any of our settings or email accounts yet suddenly both accounts in Thunderbird will cause a "connection to server timed out" error. I have checked the outgoing and incoming mail server settings and the names and port numbers are correct and so are the username and password entries. What might be causing this all of a sudden? The email accounts have been working fine for months and then suddenly last week we started getting this error. I have also tried increasing the value for the IMAP timeout in config.editor but it did not help.