I have problems opening attachments on our exchange server. My IMAP accounts work well, no issues opening the recognized attachments. But when I click the attachments on the exchange account, 9 out of 10 times it breaks.

Basically, once I click it it shows me like 10% downloaded instantly, and the bar stays there. Some seconds later I receive an error message: "File couldn't be downloaded -- Failed to download document, got HTTP response: 500". In some cases, it is an 503 error.

In case this is exchange related, I would be glad to receive hints which options I have to look into (have exchange and firewall/router admin access). The funny thing is, that it sometimes works! So I am wondering if this is really a problem with exchange...

Hoping for you guys to help me out once again.