Error AADSTS50105 encountered when logging into BibliU

Issue:
A managed account using SSO with Microsoft Azure AD may encounter the AADSTS50105 error when trying to log into BibliU.

• The account is automatically redirected to the Microsoft login page.
• The user successfully authenticates using their Microsoft UPN and password.

• However, the following error is displayed:

  AADSTS50105: Your administrator has configured the application BibliU 
  ('<APPLICATION_ID>') to block users unless they are specifically granted 
  ('assigned') access to the application. The signed-in user '<email address>' 
  is blocked because they are not a direct member of a group with access, 
  nor has access been directly assigned by an administrator. 
  Please contact your administrator to assign access to this application.

Cause:
The Azure AD account does not have permission to authenticate via the Azure AD application configured for SSO with BibliU.

Solution:
Contact the Azure AD administrators to perform one of the following actions:

Option 1: Allow all users in Azure AD to authenticate via BibliU.

• Go to https://aad.portal.azure.com/
• Navigate to Enterprise Applications > BibliU
• Open Properties settings
• Set "Assignment required?" to No
• Save

Option 2: Assign permission to the specific account experiencing the AADSTS50105 error.

• Go to https://aad.portal.azure.com/
• Navigate to Enterprise Applications > BibliU
• Open Users and Groups settings
• Assign the account directly to the application or add them to a group that already has access.