If Gmail rejects a message because authentication is missing or has failed, check the sending domain and the service that actually sent the email.

Google requires at least SPF or DKIM for senders. Bulk senders have additional requirements, including SPF, DKIM and DMARC. A missing SPF record is therefore not the only possible cause.

1. Read the complete delivery error.
2. Check the sending domain in your DNS panel. Include every sending service you use, such as EDIS, newsletter tools and external mail providers.
3. If you need help, send the error message to EDIS support and identify the sending service.

See Google email sender guidelines for the current requirements.