Why does my email not work?

Why does my email not work?

I don't know what to do.
I always get the 
550-( mail-pf0-f173.google.com ) [209.85.192.173]:36415 is currently not
550 permitted to relay through this server.

Want to use zoho. I used to have a self hosted website with it's own email. Now I moved to Shopify and want to use ZOHO.
What must I change in my settings?



I even tried deleting the old mail related ones, but nothing works!