I have been trying to configure the Merge replication in our small company for several people.

My conditions:

1. Publisher is on Google cloud behind a firewall
2. Publisher is accessible only via IP address
3. Subscribers are on personal laptops
4. Without domain
5. Publisher SQL Server works on non-standard port (15333 instead of 1433)

If shortly I when I try to check synchronization status on a subscriber I see this error:

On both sides I configured a SQL Server user for the connection (the same name and password):

I read a lot of topics, but could not solve my problem.

Only one thing I suspect: subscriber tries to connects to the default SQL Server port (1433). I see in ProcMon that the replication process tries to access to the publisher several times:

But it looks like the connection is going to the 1433 port, not to my 15333, which is desired.

Also I tried to add the publisher IP address the the Windows host file. Now I can ping/connect to SQL Server using the name, not only the ip address. But, unfortunately, it did not help to resolve the main problem: replication.

I appreciate any ideas or proposals on how I can fix this issue.

Thanks.