Unable to create migration endpoint in 2007/2013 Hybrid

Hi Ian,

Maybe the error is that Exchange Servers group could be a nested member of Organizational Management group. Once you removed it from Organization Management Group and set the admincount value to 0 and then reboot, the issue could be resolved.

You can see this article that describe your error https://support.microsoft.com/en-us/help/2975731/-access-is-denied-error-when-you-try-to-move-mailboxes-to-exchange-onl