I/O Modules - Web server - Problems with port forwarding

Issue

After port forwarding in a router or switch, it is not possible to connect to the modules’s web server.

Check if the IP address is set correctly. Make sure to restart the module after changing IP address.
Check if the default gateway in IP configuration is set correctly.
Make sure that the IP address is correctly typed in a web browser. Make sure that the address is started from 'http://'.