How to return connection to any local ip?

Question

Browsers

When you try to connect to any ip that is on the router's shared network, it says in the browser that there is no connection.
192.168.100.1 enters the router itself, but if I start ftp on the phone from 192.168.100.2:2121 or the web camera on the phone, there will be no connection. Everything worked, but at some point in time it stopped, I don’t know where to dig and where to look. Tried to add exceptions to the windows firewall, turned it off, but it does not help.

Answer 1

The most obvious thing is to reset the router settings to default if it messed up.
Not obvious, start with a tracer and see where the plug is and dance from it. Maybe the port is closed, etc.