"You are not allowed to access this application."

"You are not allowed to access this application."

I created an Application with user A. I've shared it with user B.
User B can see the application when she logs in but when she clicks on the app it say:
"You have logged in as <userBemailaddress>. You are not allowed to access this application."

The user is active on the zoho creator settings page.
All the forms are shared with the user.

I've tried to remove the user and all of her permissions and re-add but still no luck.

What is weird that it was working yesterday.