Great to see you’ve attempted to troubleshoot this issue! If you are able to log in via your mobile using data rather than WiFi, this indicates a possible local network error. Have you tried restarting your WiFi modem recently?
For some people, the easiest way to reboot the router is to unplug the power supply, wait 30 seconds, then plug it back in again. Alternatively, there may be an on/off switch on the back of the router, in which case you can use that to turn it off, wait 30 seconds, and then turn it on again.
Let me know how you get on!