Given poor terminology and lack of details, I'd guess what is going on here is your new router is set to have the DHCP server feature turned on, and is issuing your server a different IP address than its prior 192.168.0.22, so this app you use for accessing it, is looking for it on 192.168.0.22 still.
If that is the case, either set a static IP on the server in the 192.168.0.(n) range... might as well make it the same 192.168.0.22 so you don't have to input new IP # in the app or look for it on the lan again, OR, note the mac address of the server's network adapter and set the router to issue that mac address, the same old 192.168.0.22 fixed IP. The latter also depends on whether the router supports this feature.
I could be completely wrong with all the above, just best guess. Maybe I should back up a bit. You had an old router, correct? Was it configured in any way or using all defaults? I don't know how the variable table works for DHCP issuing IPs, if it would have consistently continued to issue same one to the server or how you got the app set up to access it in the first place. You should look at your router connected client log to see what IP the server is, if nothing else...
If the above is beyond your ability, you might just be able to uninstall the app and reinstall and then during the reinstall routine it finds the server's new IP address, but if using DHCP on the router, then that IP is subject to change in the future if not set to static on the server. If your only method (that you can accomplish) to access the "server" is through the app, then you could temporarily gain access this latter way, get into the app, and then set the server to a nice, easy to remember IP, for example if router is 192.168.01, and 192.168.0.2 is untaken, set the server to that fixed IP address using the app. because it's easy to remember it's only one # past the router IP, then next time you swap routers, you already know what its IP is and the app doesn't need to be told or find out a new IP for it.