Mailspring account setup error

Connecting to COX server fails with message

SMTP Last Response Code: 552
SMTP Last Response: message rejected. Refer to Error Codes section at Email Error Codes for more information. AUP#CXSNDR

Cox message indicates it is a Mailspring issue. "Your email failed authentication checks against your sending domain’s SPF, DomainKeys, or DKIM policy.

Any suggestions would be helpful