I'm getting this error "The remote procedure call failed and did not execute." on a web application that is supposed to display an Exchange calendar. After this error appears I get the error "The requested resource is in use." I think the first error is caused because this web application is set up as an "out-of-process" high-isolation web application and it fails. The second error message may be a better clue as what the real problem is. Can anyone give me any clues as to why a web application that connects to an Exchange mailbox would find the requested resource is in use?