My iCloud password isn’t working
Why can’t I download apps or fix my phone keeps asking for iCloud password and not working.?
iPhone 7 Plus, iOS 12
Error message(s)?
Do you have access to another WiFi network where you can try? That has worked for several people.
Try a restart.
Restart your iPhone, iPad, or iPod touch
Try a forced restart.
If necessary
Do a backup and try a factory reset. Then restore from your backup.
Backup - Restore your device from an iCloud or iTunes backup