Android Facebook Sync doesn't activate in System"Accounts/Sync" Setting

I re-added my Facebook app account to "Accounts and Sync" (in System Settings) but it won't activate sync. The button stays grey. Sync of overall phone is on.

I have Huawei m931 running Android 4.0.4. Here is what I did:

1. Reinstalled app on phone, after clearing cache, signing out of chrome.


2. New username/Email of my Facebook account is same as my primary Gmail/Chrome email address.

Of note is I have 2 gmail, and 1 Yahoo accounts. Also, the phone's number is used in both gmail accounts for security alerts (don't know if is relevant)

Help!, am new at this