Outgoing Server Error while trying to integrate Zoho and Gmail

Outgoing Server Error while trying to integrate Zoho and Gmail

I have enabled POP on my gmail account and used these settings in Zoho from this page:
https://www.zoho.com/crm/help/zoho-mail/configure-gmail-account.html

And keep getting this error:

Please enter a valid Outgoing Server.

Overall it's been very complicated to simply sync these two programs and/or to get clear information on doing same.