Unable to add zoho account to gmail SMTP only

Unable to add zoho account to gmail SMTP only

Hello,

I'm trying to add my zoho mail account to gmail, for sending email purpose only.
I tried the following settings

smtp: smtp.zoho.com
ssl 465 ->
Authentication failed. Please check your username/password.
Server returned error: "535 Authentication Failed , code: 535"

smtp: smtp.zoho.com
tls 587 ->
Authentication failed. Please check your username/password.
Server returned error: "535 Authentication Failed , code: 535"

I get this message for all 4 of my accounts

Is smtp service offered to premium accounts only?

Thank you