Steps I'm taking: 

1) In campaigns I'm clicking "Contacts > Sync Services". Zoho CRM is the first choice and it says "Accounts not associated". When I hover over the image a button appears saying "Associate New Account". I click this.

2) A new window pops up describing what this integration will do. I click "Continue"

3) Upon clicking the Continue button I'm taken back to the Sync Services page and an error pops up at the top of the page saying "Organization is already integrated".