Please help with mobile sync

Please help with mobile sync

I am completely new to the Zoho applications.  I'm attempting to enable the mobile sync functionality from my LG G2  android phone (version 4.2.2).  

No matter what options I put in for username and password (full email, partial with separate domain entry) I get a message that authentication failed due to wrong username/password.  However, the exact same credentials log me into the Zoho online services just fine.  I've even changed passwords to make sure it was not a case of being locked out.  

Thanks in advance, 
James Macy-Simpson