Exchange Hybrid – Free/Busy information not working

When upgrading an SSL cert last week i had to run the Exchange Hybrid Configuration Wizard again. Of course when you update something like this or the AD Connect something is broken….

Before the Free/Busy was working from Microsoft 365 Exchange Online to the On-Prem environment.

After checking the relationship i saw that the sharing code was empty again.

Get-OrganizationRelationship | select TargetSharingEpr

Resulted in an empty response. To fix the Free/Busy time this needs to be filled in, in there are subdomains. If you have let’s it’s fine, but if you have it goes wrong. Because it tries to reach instead of Even if you have some CNAME records, it takes to long.

Instead of letting autodiscover finding out what the URL is, as told in the beginning, i had this issue in the past, simply put the Hybrid servers in the TargetSharingEpr directly. So

Set-OrganizationRelationship -TargetSharingEpr -Identity yourmicrosoftidentity

After this, the Free/Busy will work again.