ZOHO Sync between CRM & Campaigns - missing contacts

ZOHO Sync between CRM & Campaigns - missing contacts

I've been trying to reconcile/match all contacts between ZOHO CRM & Campaigns.  We have over 4,500 contacts.  I have found a number (approximately 260) contacts that exist in CRM, but I cannot find any record of them in Campaigns.  I have searched the bounced, duplicate, unsubscribed, opt-out, etc. listings with Campaigns, BUT I can't find any record of these contacts.

How do I further research this?