My iPhone is not connecting to iCloud storage I don’t know why

Maybe you are having a server problem. There have been quite a few Apple server connection problems lately. See If you can't connect to the App Store, iTunes Store, or other Apple services https://support.apple.com/en-us/HT201400. Among other things, see Check Apple’s System Status page to be proactive in knowing if there is a server problem when you want to access a particular one.

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.

Reset Device.      

If necessary

Hard reset.        

Do a backup and try a factory reset. Then restore from your backup.

Restore to Factory setting.      

Backup - Restore your device from an iCloud or iTunes backup.      

Buy more iCloud storage.