The SMTP of ZOHO are listed in many blacklists and for this reason emails are going straight into spam.

How can I use fully custom SMTP servers?

"Send mail as" found on "old settings" seems not to be a good idea for 2 facts:

1. It is single user based (one email, one config)

2.The recipient can see the email in the middle

Is there some workaround?

Thanks, Paolo