Unable to connect to server over SMB via the internet.

Hello,

I have a 2014 Mac Mini set up as a server for my RAID drive for both access inside and outside my home. I have always used AFP to share the drive, up through macOS 10.15. There has never been an issue connecting to the server from either the local network, or via the internet. Now that this has been updated to macOS 11, and AFP has been deprecated, I have tried to connect via SMB. While I can do so on my local network, I have been unable to reach the machine to connect from the internet. I simply get an error to the effect of "There was a problem connecting to the server, The server may not exist or is unavailable," etc. I have forwarded TCP ports 137, 139, and 445, and UDP ports 137 and 138 from the router to the Mini. I am able to Screen Share with the Mini from off site via the internet, so it is not a physical connection issue at all.

I am unable to figure out why this will not connect properly. Is there a port or some other option that I am missing here?