Hello @CatherineMcDon ,
Here are some general best practices for delivery.
Delivery can have a lot of variables, from elements on our side, on your side, on the recipient's side, and in their email system company's side. It's typically best to set up additional authentication for your emails, such as self-authentication if you have your own domain.
If you'd like to learn more about safelisting, and what it entails:
Safelisting domains in a security system
Safelisting email addresses in an email client or security system
If you're wanting more in-depth, specialized insight on your current deliverability, it'd be worth speaking with one of our Delivery agents.
