When attempting to login to OWA with valid credentials, the login screen reappears without any form or sort of error message. Despite this the logon procedure has succeeded, because when I re-enter the OWA URL my mailbox is opened.
I am unsure as to the cause of this problem. The strange thing is that it does not happen all the time. Exchange is installed on the domain controller, but other than that I can't think of any possible causes.
Could it be a misconfiguration somewhere? Perhaps something to do with the IIS or DNS configuration?