Suddenly my wifi won't work on my phone. The wifi is fine on every other device so no issues with the router. I have tried a restart, full off and on, forgetting the network, resetting network settings...nothing is working.
I tried to do a backup so I could do a hard reset but it failed and said I can't backup using mobile data (after it made me wait until 100%).
Usually just clearing the cache etc in Settings_Apps_Wifi_Storage_Clear cache / data works.
In regards to backing up check in any relevant settings that maybe stopping an update or your mobile data isn't strong enough.
Backing up using Mobile Data certainly is an option as i do this all the time.
maybe back up to any relevant sd card what you can and.jf you've performed a recent back up to Samsung Cloud then you should retain most if not all your information. However that's a choice for you to make.
You may have to wait until the Samsung Experience Store or Samsung Service Centres re open after the COVID-19 pandemic ends.