Valimail experienced a partial SPF response service degradation on June 3rd from 05:20-14:00 UTC. Email Senders that utilize SPF only (do not have DKIM configured and are not in your Netblocks) were affected.
If your domain is at a DMARC policy of quarantine or reject, email senders that are configured as enabled senders with no DKIM keys may have been affected. You may see this issue reflected in your DMARC authentication reports. If business critical email was sent during this time period that is showing as failing in your authentication reports, please re-send the mail.
Valimail has tested various senders that were affected and confirmed that after the incident we are responding with the proper SPF response.