Free/busy is not working between our Office 365 tenant and on premise Exchange. I've run the free/busy test on testconnectivity.microsoft.com and the test fails. The test fails because the ASURL points to the wrong on premise server. I've set the external URL on both of my on-premise CAS using Set-WebServicesVirtualDirectory and I've re-run the hybrid wizard but the ASURL still shows the wrong address.
How can I change this?