Users cannot access SharePoint via SSO SAML, and the following error appears on the Microsoft Office 365 side.

Error access denied

• Microsoft Office 365

The impacted users do not have permission for SharePoint on the Microsoft Office 365 side.
 

1. Request the administrator to grant the affected users appropriate permissions within the Microsoft Office 365 environment.
   1. Providing the necessary access levels will ensure that the impacted users have the required privileges to carry out their tasks effectively.
2. If the problem persists after the permission adjustments, escalate the issue to Microsoft's support team.