'Portlet is temporarily unavailable' error for Sharepoint Connection

Issue

• A day or two after successfully configuring a Sharepoint Connection, I now see a "Portlet is temporarily unavailable" error in the UI and the following error in the Liferay logs when attempting to open the Sharepoint repository again:
  

  ERROR [https-jsse-nio-8443-exec-10][render_portlet_jsp:131] null
  java.lang.NullPointerException at com.liferay.sharepoint.rest.
  repository.internal.document.library.repository.authorization.
  oauth2.SharepointRepositoryTokenBrokerFactory._getSharepointRepository
  Configuration(SharepointRepositoryTokenBrokerFactory.java:59) 

Environment

• Liferay DXP 7.2 Fix Pack 4 to Liferay DXP 7.3 GA1
• Liferay REST Connector to SharePoint version 3.0.0

Resolution

• This behavior has been reported and fixed in LPS-121069. This fix has been released in the Connector to Sharepoint version 4.0.0, which required DXP 7.3 Fix Pack 1. 
• If still on DXP 7.2, please create a Help Center ticket requesting a hotfix of the Connector that includes LPS-121069.

Additional Information

• Liferay REST Connector to SharePoint