I`ve the same issue, but it's between Edge and Front-End.. but you can try to change the connection port at Edge.
Add another Port to allow connections on Front-End (By Default, only 5061 MTLS). In my case, i`ve added port 8058 MTLS
In Edge Server, Next Hop Server, put 8058 port on the Next Hop Communications Port...
Solved :-)
Please, let me know if this is helpfull
Regards,