Protocol Mismatch using netcat

Trying to add an LTM to a GTM using bigip_add. I keep getting Connection Refused over port 22. Originally, I did not have that port allowed but I've since set it to be allowed. It's still displaying Connection Refused.

 

When I run nc -v -s GTMIP LTMIP 22, It originally says that the connection succeeded but then it immediately goes to a Protocol Mismatch. When I run the nc again, I get connection refused. If I reboot the LTM, I can get it to connect again but then it throws the Protocol Mismatch error again.

 

I'm at a loss here so any help is appreciated!