Clicking on a set of groups gives HTTP 500 error

Openfire Openfire Support
1

We are running Openfire 3.9.3 with MySQL and Active Directory. We have 470 plus users so there are 5 pages showing 100 users per page. From the openfire admin console, after selecting users, when I click on 2< i get the following message:

HTTP ERROR 500

Problem accessing /user-summary.jsp. Reason:

Server Error

Caused by:

java.lang.NullPointerException

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The others 1,3,4,5 work fine. How do I fix this.