Outgoing messages are being rejected by a DMARC check.
SMTP error from remote mail server after end of data: 550 5.7.1 Email rejected per DMARC policy
SolarWinds Mail Assure
Message failed SPF or DKIM record check, or SPF or DKIM alignment check performed by the recipient mail server, and was rejected by the recipient mail server per sending domain's DMARC record specifications
Publish/update SPF and DKIM records for sending domain to accurately represent sending IP addresses and messages permitted to send on behalf of the sending domain