For some reason ACT Add-in and Address Book don't seem to appear in Outlook 2016 on only one of our clients. We have 6 other clients which have the same exact setup and work fine.
I have gone through every single step of this knowledge base article (https://help.act.com/hc/en-us/articles/360024413433) but still didn't help. In some steps they mention to repair some registry keys but those registry keys don't even appear on this client.
Other than the steps in article I have already tried uninstalling and reinstalling both ACT and Outlook 2016 multiple times.