Can't create an email alias or add email forwarding rule

Hi there,

Wasn't sure where to post this topic. Let me know if it would be better off elsewhere. My client sent out a test email campaign and it went straight to her spam folder. Her email address couldn't be verified, so I offered to set up an alias [hello@katrinameister.com] that we could then forward to her regular address, per SquareSpace's email campaign best practices. When I went into the domain panel to add a forwarding rule, the button was grayed out and it says I can not add or edit email forwarding rules at this time due to MX records [see screenshot attached].

How do I solve this?

Thanks!

Brenda