Thanks for enabling the custom error @Phineas
To make it simple. you can leave all settings as it is in the home page and make sure it is working for you.
For your colleague, the ground rule is to ask your colleague to sign in to the portal via Azure AD or using local login (not recommended) then the portal will create a contact.
Once Contact is created then as an administrator you can assign a web role to her.
In your case, I can see you have created a contact for your colleague.
Hope this will fix your issue.
------------
If you like this post, give it a Thumbs up. Where it solved your request, Mark it as a Solution to enable other users to find it.
