The process of building custom applications and tools that interact with Microsoft SharePoint, including SharePoint Online in Microsoft 365.
Please note that this forum is a public platform. Kindly ensure that you hide any personal or organizational information to protect personal data.
You can refer to AI's answer first, particularly the guidance on opening a support request through the appropriate channel and providing the correlation ID and other diagnostic details.
In addition, since both SharePoint Online and OneDrive are redirecting to PolicyViolationThrottle.htm while Exchange Online, Microsoft Entra sign-in, and other Microsoft 365 services remain accessible, the issue appears more likely to be related to the SharePoint/OneDrive service itself rather than a general authentication or licensing problem.
As this is a peer-to-peer forum, members do not have access to tenant backend information and therefore cannot verify whether a policy enforcement, compliance restriction, service suspension, or other service-side condition has been applied to the tenant. Such verification would need to be performed by Microsoft Support.
When working with the Microsoft Support team, you may also wish to ask them to confirm the current SharePoint Online service status for the tenant and whether any tenant-level restrictions or enforcement actions are affecting SharePoint and OneDrive access.
I hope this information helps.