Alwayson - Problem with adding secondary replicas

I installed always on setup on my laptop (testlab) with 3 VMs. One domain controller and 2 SQL instances(Plaed to have it as one primary and one secondary replica). Everything went well until I wanted to add the secondary replica to the Availability group.

Please find screenshot attached. Yes I have already changed the port to 1433 in tcpip settings and have also added an exception for sqlserver in the windows firewall. Both of the servers are on the same cluster network. Not sure what else I am missing here