IPB v2.1.x: The option to activate ParaChat is not present

Problem:

I ordered ParaChat for Invision Power Board v2.1.x. But the option to add my ParaChat Site ID to activate ParaChat in my IPB is not present. What should I do?

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Solution:

Log into your Invision Power Board as admin, and open the Admin CP. Click the "Tools & Settings" tab. Under "Maintenance" click the "Clean-up Tools" link. Click the "Run Tool" button under "Remove Duplicate System Setting Groups from IPB 2.1.x".

Once the tool has run, the ParaChat activation option will be present.