Email forwarding off domain name leaves error "failed permanently"

I’ve done a bit of searching and I can’t quite find the answer.

My domain name is hosted by Hover and site hosted here. I’ve purchased a $5 email forwarding option through Hover that should be handling my emails to admin@mydomainname.com to my personal gmail account. When I send the email, I get 2 responses –

1. The email returned to me in full
2. The error email, which starts with: “Delivery to the following recipient failed permanently:”

I know I’ve seen multiple questions similar like this online, but most conversations go through a PM after the initial question, so I can’t find answers.

I tried pointing the MX record at Hover.com to my server, but I’m not sure what I put there is correct, and I’m just very confused. Nothing is forwarding, and I can’t have people that email that account get a bounced error message.

Thanks for any help you can give! Really want to get this sorted out this week.