Since I installed the platform could make calls to IP and URI Externals directions, but a few months ago I could not make calls to URI Externals but yes to a IPaddress external from devices registered in the VCS Control,devices registered in the VCS E can call normally.
This is the search history and error is displayed is Resource unavailable - Loop detected.
I do not understand because it appears as firstname.lastname@example.org instead of @ cisco.com which is the original domain.
Can you provide a copy of the entire search history, transforms, and search rules. It could be a transform or search rule is changing the "rtp.ciscotac.net" domain to become yours, creating a loop.
You're "Replace CUCM domain" transform is changing the domain. When using regex to transform addresses, you need to be as specific as possible to not create false positives. Instead of using .+ after the @ symbol, I'd specify what the actual CUCM domain is.