I would like to start from scratch with OCM, but I have over 5000 copies of the exact same contact in my OCM database. This contact is not in my address book.
You can bulk delete contacts under Outlook 2016 client People tab.
Then, you can filter the contact you want and remove them.
Note: please back up all Outlook contacts before doing this to avoid mistaken deletion.
After doing this, try to force update the OCM contacts by clearing the IE cache via the steps below:
Please go to IE settings > General > Settings under Browsing history > Caches and databases > delete cache files for the website "outlookapps.com". Then, restart Outlook 2016.