REGISTER SERVERS - ALWAYS ON

Myself configured SERVER1 and SERVER2 connected to DOMAIN CONTROLLER.

Everything is working fine.

While using the REGISTER SERVER  from SSMS  on Server (SERVER2) is configured  / accessing for SERVER1.

Your steps...

Yes it is warning!

Should I proceed installation what should I check after Installation.

Will I deprived any further obstruction as the error say it should allow PORTS for the oncoming...

Thanks for the solution though I have removed Windows Firewall still getting the same error.

Any suggestions please.