503 Service Unavailable Error When Accessing Admin Panel

Hello,
I applied this article How to remove port 8090 from CyberPanel
my cyberpanel works fine but I go server sratus ==> change port and I change port to 40.
Now I can’t access my panel. when I access to my panel the message appear:

503

Service Unavailable

The server is temporarily busy, try again later!

I need help please. how to solve this problem? please help me

Did you added the port in firewall before removing from the cyberpanel

no i didn’t

please how can i add the port in firewall with putty? can you help me sir?