Confirm other devices work
This is the most useful first split in the troubleshooting tree.
Restart the affected device
A normal restart can clear temporary network state.
Review supported network settings
Use the device manufacturer's current instructions before forgetting networks or resetting network settings.
Consider app-specific symptoms
If only one app fails, Wi-Fi may not be the underlying problem.
General consumer technology information only. Interfaces and menu names change. Before resets, reinstalls, storage changes or other major actions, verify that important data is backed up and use current manufacturer/service-provider instructions.