iOS 6.1.3 update is not working with my exchange account

Since the update to iOS 6.1.3 my Exchange account broke down e.g. I do not receive any mails, the exchange server is not responding any more. The last time this happened with iOS 6.1, resolved with 6.1.2 and now i have the same problem again.

It seems some people had problems with their gmail accounts, surprisingly my gmail account works fine. Activating and deactivating and even deleting of either exchange mail account or gmail acount did not solve the problem.

The following accounts are active:

iCloud (only e-mail deactiveated, seems to work fine)

Exchange (the one that doesn't work)

Pop Mail account (works fine)

T-mobile germany (imap, works fine)

Google mail (works fine)

Any suggestions?