I've only seen this once and I think it was due to bad installation, since we had to change hostnames and port numbers AFTER the install, so it may not happen to many people but if it does... hopefully this will save you some time :)
*You want to go into your SQL Server Management studio and then go to, your CRM_CONFIG Database.
*Expand Tables and look for the record "Deployment Properties"
*Right click and select "Open Table"
*Navigate down to "AsyncSdkRootDomain" and then accross to "NVarCharColumn" and fill in the correct hostname and port number (Usually something like 'CRM:80')
*Do the same for "ADSdkRootDomain" and "ADWebApplicationRootDomain"