Leopard Mail / Thunderbird with Exchange server issue

hello everybody.
I upgraded to leopard 2 weeks ago and Thunderbird was working fine with the MS Exchange server we have here at the office. When I came to work on monday it didnt work anymore.

I´ve tried all kinds of tricks, used an ip adresse instead of the server name, imported a new certificate, totally badgered everyone in the IT department and so on.

I cant connect with Mail either.

The error I get with Thunderbird is a connection time out, but in the lower left corner of Thunderbird it say´s it´s connected to the server, then the connection times out. I also get "Unable to connect to you IMAP server. You may have exceeded the maximum number of connections to this server. If so, use the Advanced IMAP Server Settings dialog to reduce the number of chached connections." this doesnt work either.

I´ve always had trouble with Mail and Exchange server but Thunderbird was working, even though I would prefer to use Mail.

Has anybody seen this before.