I have just been looking at a problem with IIS (OWA outlook web access and sharepoint http://companyweb were not responding) and remote access to the RDS server had stopped. The application event log was full of event ID 1500 and 1501 for the user spwebapp.
The Windows SBS 2011 is running Exchange/OWA and IIS and has the remote gateway configured to redirect to the RDS server.
I restarted the remote gateway service which fixed the remote access problem.
The next problem was OWA and Company web not responding. I restarted IIS by running the IISreset from an admin command prompt but this didn’t change anything.
As you can see the event were happening frequently (about 20 a second). I have no idea when this started as the log was full and overwriting older events.