If you have an untrusted AD-connector that suddenly cannot connect anymore, after applying UR7 or later it could be due to an LDP connectivity issue.
In my case, the Operations Manager log on the workflow server logged the error: The specified domain does not exist or cannot be contacted.. each time the connector started.
DNS resolution of the domain name worked fine, and I could connect manually to a DC on port 389 using ldp.exe, from the workflow server.
However, because of the updates in the AD-connector done in UR7, SCSM is now also connecting to the DC on port 389/UDP instead of only 389/TCP.
So go to you network guy and ask him to open up for both TCP and UDP on port 389.
You can troubleshoot the LDAP connectivity yourself using this tool:
PortQryUI (https://www.microsoft.com/en-us/download/details.aspx?id=24009)
