FireFox browser Add-on

We recently purchased LanguageTool on-premise service, we created a registry entry at KEY_LOCAL_MACHINE\SOFTWARE\Mozilla\ManagedStorage\languagetool-webextension@languagetool.org that contains a path to a JSON file where all managed settings are stored. Firefox browser add-on still points to the Cloud rather than the on-premise server. The steps they took are listed below; Any assistance is greatly appreciated.

First, I created C:\Temp\MozillaFireFoxLanguageTools.JSON with the following information:
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Second, I created the following registry key:

Third, I installed the LanguageTool add on. I tried closing and restarting FireFox, and then rebooting my computer. The configuration for the add on still shows to be pointing to their cloud instance:
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The key you use seems to lack .org. at the end. The full key is KEY_LOCAL_MACHINE\SOFTWARE\Mozilla\ManagedStorage\languagetool-webextension@languagetool.org

Yes, I fixed it, it is working now. Thank you so much @dnaber