SSH forwarding issue. "Permission Denied"

Solution 1:

I found the cause. selinux was blockingf me. I had missed the error when I trolled the audit log previously, although I don't know how I could have missed it.

type=AVC msg=audit(1609794646.746:434): avc:  denied  { name_connect } for  pid=11043 comm="sshd" dest=22 scontext=system_u:system_r:sshd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:ssh_port_t:s0 tclass=tcp_socket permissive=0

All I had to do was set the "nis_enabled" boolean to enabled, and the problem is gone. :)

setsebool -P nis_enabled=1