Zoho mail to Teaminbox

Hello,

We're searching for new mail program.
Now I'm testing a bit with zoho mail and team inbox.

My findings in the research:
Pop mail throught zoho mail is almost instant.
Any pop or imap via external provider takes a couple minutes to 15 minutes before it shows.

So I like to get the zoho mail for my addresses and receive them in teaminbox.

But somehow I can't get it to work.