Forwarding external calls

Hi

I’m having a problem when call forwarding extensions to outside numbers using the Follow Me feature . Internal calls are forwarded to the outside number fine. External callers receive the msg “The person at ext X is unavailable”. I think this is related to the passing of CLID, but I’m not sure how to resolve it. If I forward to an outside number using a ring group with the Fixed CID set, it works fine. My provided states that I need to use P-Asserted-Identity in the call flow, and I have that set in Settings>Advanced>SIP sendrpid. Im running FreePBX 13.0.192.9.

Can anyone point me in the right direction please?