Can't update WordPress with Admin Users

I can’t update WordPress. I’m logged in as User Admin and see the message ‘WordPress 5.5.1 is available! Please notify the site administrator.’ but I am already logged in as administrator.

This occurred after transferring a staging site to live due to a redesign. The staging site wouldn’t allow me to update using User Admin either.

So far I’ve checked with the hosting server tech support. They couldn’t figure out a solution.

I’ve tried creating new admin users but those users don’t allow the update either.

I’ve checked wp-config.php for define(‘DISALLOW_FILE_MODS’,true); but it’s not there.

Any ideas on how to resolve this?