Email Delivery Incident - May 2026

This is not the kind of post we ever want to write, but we need to be upfront about an issue that affected Appbox transactional emails.

Short version: Elastic Email, our email delivery provider for more than five years, paused our account without warning. We received no alert email and no advance notice that sending would be stopped. We only found out when a user contacted us to say they had not received an expected email.

That's not good enough. We should have caught it sooner, and we're sorry.

What Happened

For roughly 24 hours, some transactional emails from Appbox were not being sent. This included things like signup emails and invoice notifications.

When we investigated, Elastic Email showed our account as paused and told us to contact support. We contacted support immediately. Transactional email is core infrastructure for Appbox, and we could not leave it broken.

It took Elastic Email around three hours to manually review and reactivate the account. Their explanation was that the account had been placed under review by an automated security check. They also said that, for security reasons, they would not provide specific details about what triggered it.

Impact

More than 600 emails were delayed because of this.

Those emails have now been sent. This was a delivery delay, not a permanent loss of email, but it still meant people were left waiting for messages they should have received straight away.

What We Did

As soon as we confirmed what was happening, we started moving outbound mail away from Elastic Email.

We added SMTP2GO as a new provider and routed all mail through them so delivery could resume immediately. Once Elastic Email reactivated the account, the delayed mail that had been held there also resumed.

Our View on Elastic Email

We have had a relationship with Elastic Email for over five years, but pausing a transactional email account without advance warning or immediate notification is not acceptable for a core infrastructure provider.

We're now reviewing whether the move away from Elastic Email should become permanent. Based on this incident, we can no longer recommend Elastic Email to customers who rely on time-sensitive transactional email delivery.

What We Are Changing

SMTP2GO is now handling our outbound transactional email. We are also asking them directly how account reviews are handled, what warnings are sent, and what escalation path exists if their systems ever flag us. We need clear assurance that mail will not be silently stopped without warning.

We're also putting additional checks in place on our side. If a provider-side issue ever affects email delivery again, we want to know about it immediately rather than finding out from a user.

Sorry

We apologise to everyone affected by this. Appbox emails should arrive when you expect them to, and in this case they did not.

The delayed messages have now been sent, email delivery has resumed, and we're making changes to make sure this does not happen again.

---

If you were affected by this issue or have any questions, please contact us at support@appbox.co.