Schedule reminders configured for all the available entities except for participant will send reminder on exact same day match in your case it would be on 7th day after expiry date.
For events participant its different, in current version of civi if you have configured send reminder for event start date after 7 days than it will send reminder for all the ...
Since you are on wordpress 5.5 it s mandatory to upgrade civicrm to 5.26 or more (5.28.x preferred) else all your front end civi forms will not work
There are a few items here:
It's safe to upgrade CiviCRM from 5.26 to 5.30 in a single step. As always, back up your database first, and if you need to restore it, it's safest to drop the existing contents before reimporting the backup.
Notices should not be configured to appear on a production site, they're mainly of concern to developers. Since you ...
I have had a similar problem with a WordPress install. In my case the Anonymous role of WordPress missing.
The Wordpress roles can be checked with
wp role list
I created the new role with
wp role create anonymous_user 'Anonymous User'