Error
405 Method Not Allowed
Cause
Most Exchange servers are configured to accept standard HTTP requests of GET or POST type.
However, the Exchange Web DAV protocol also uses other methods, also known as verbs, such as PROPFIND, SEARCH, or X-MS-ENUMATTS. These methods may be blocked by your IIS configuration.
Resolution
When migrating from Exchange 2007 environments, check which verbs are allowed in your IIS Exchange configuration and verify that the methods listed above are allowed.