I recently forwarded ports 5060, 5061, and the RTP ports to my PBX (moved away from Cloudflare tunnels to avoid push notification issues). I turned on TLS for SIP and also SRTP. SMSConnector used to work fine, but I’m not sure what happened and I can no longer receive messages to the DID, but I can send from it. SMS did work when I used to use a Cloudflare tunnel for my PBX. I checked freepbx.log and some other log files, but nothing is there when I send a message to the DID, which makes me think the messages aren’t hitting my PBX. My configuration for voip.ms is correct, as I tested the configuration with webhook.site and it was able to reach it. So, it must be something with my PBX. I was thinking it had something to do with TLS or not forwarding some port(s). I’d appreciate any help!
I just had to forward port 443 to the PBX and go to firewall services and allow the secure web management (HTTPS) option for the internet 
I am yet to set sending messages. Tried it and it seems it does not work by default (even within local network), but that is not my priority for now. I will have to deal with it later so I followed your experience with interest.
I have FreePBX behind NAT router, and if I forward port 443 to FreePBX it makes Admin web interface exposed to the public.
How to avoid that?
Try this:
Admin > System Admin > Port Management and change the HTTPS port for the Admin UI. I don’t know if this’ll work ‘cause you might have to end up forwarding this as well anyway
You need to have the access to reach it remotely. So you either need to leave it open or setup firewall rules to allow certain traffic through. You could also setup a VPN to access it over.