Microsoft Office 365 may encounter the following provisioning error when pushing profiles from Okta to Office.
 

An error occurred while assigning this app.Automatic provisioning of user  to app Microsoft Office 365 failed: Could not push profile for Office 365 user, received error: Could not push profile for Office 365 user , received error: [syncOperation=Set, alias=null, sourceAnchor=, userPrincipalName=, mail=, displayName=, commonName=null] errorCode=DirectoryServiceException, errorDescription=An internal error has occurred. This operation will be retried during the next synchronization. If the issue persists for more than 24 hours, contact Technical Support., info=null

• Okta Integration Network (OIN)
• Microsoft Office 365 (O365)
• Azure Active Directory (Azure AD)

The issue is caused by the proxyAddresses attribute also being added to DirectoryExtension sync. Microsoft will attempt to sync this attribute to another set of attributes, such as extension_proxyAddresses, in Azure AD.

The solution for this issue lies mainly on Microsoft's side. To solve the issue, the following steps must be completed on the Azure side:
 

1. Remove proxyAddresses from DirectoryExtension. However, it will need additional extra steps. Removing the proxyAddresses will prevent future sync issues, but the issue with the pending export will persist.
2. Create another Outbound sync rule that flows AuthoritativeNull for the extension_proxyAddresses attribute.
3. Perform a Full sync.  

Related References

• Directory Extension has some limitation in the size