HELP sending gmail using smpt to change FROM on the gmail to reflect my Zoho email address:

HELP sending gmail using smpt to change FROM on the gmail to reflect my Zoho email address:

I am really having a hard time.  I think I do it all right. But then I am wasting HOURS trying to fix problems.  I have my doamain with Go Daddy.  I changed the Cname and MX records to rerflect my zoho account.  I now can use my domain name in my new zoho address and it works properly.

Now I set up mail forwarding with Zoho to forward my mail to my basic gmail account.  It works great. Everything fine.

Then I wanted to send emial from my Gmail account but have the email reflect my Zoho email address.  Ex:  I have a folder for my forwarded mail from Zoho.  When I open that letter, i want to be able to also respond to it but NOT have it show my Gmail address.  I want it to be FROM the same address they sent the original email to, which is my Zoho account email.

What do I need to do to best set this up?  I did mail forwarding and tried multiple times to set up SMPT so that the FROM part would reflect the Zoho address.  I used the Gmail account and used my user name and zoho address, then I put 
Outgoing Server Name : smtp.zoho.com, Port: 465, Security Type : SSL in the appropriate places.  but I CONTINUE TO GET DENIED because authentication failed because of zoho server says that I am not a user???  Error 535?