DNS Records

We created a subdomain for the newsletter and it's not letting us add some DNS records. Can you please assist us with this? 

It's saying invalid for the TXT and CNAME. I tried adding just the other ones and it's saying that the email will be disconnected which we didn't want as this is just a subdomain for the newsletter. Please see below the records that we are trying to add.

TXT
smtp._domainkey.mg
k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDOi9ipHaBMysjEbhsxV5Z72tsiRKEBqYew62jvIzrGUh7gUhvvtMACdmtz/NvE3JmDjTZO572dRhWzcsWWME9YB1OSQc8IpGsh0OAEqPCLBXeGOYHIPqbVajL6yPr3993nHE/Hxx79ADl3qXEYgsoPP29H7VPF8w9fQH6jsBKpiwIDAQAB

CNAME
email.mg
mailgun.org