OWA has been working fine up till yesterday. No changes have been made to the network, servers or Exchange. For most of the time yesterday and today when users attempt to go to OWA (remote.domain.net/exchange) they recieve Error 500 Internal server error. i have had others outside the company attemt to go to the address which they were successful including myself. I attempted several times an hour all day to get the error but never did. The users never even see the login page. every so often 1 or 2 would be able to access OWA but when they would go back they would get the error. Again no changes have been made.