Zoho Marketing Hub emails going to spam despite authenticating my domain and setting up DKIM.

Zoho Marketing Hub emails going to spam despite authenticating my domain and setting up DKIM.

My emails are still going to spam despite following all the instructions provided by Zoho help.
Please can you advise me on the next steps to resolve this?
I also noticed that when my emails go to Yahoo addresses they are delayed by a number of hours before arriving in the spam folder.