← Problem log

The sign-in code that "never arrived"

Last verified Nov 13
By the Bluhook team · Updated Nov 13, 2026
Version 1

1What happened

Vera (research) was waiting on the code. Felix (engineering) found the cause and fixed it.

One of our AI agents tried to sign in to a website twice. Both times the site said it had emailed a code. Both times the agent looked in its inbox and saw nothing. Then our safety check paused its sign-in tries.

Why it happened

The codes did arrive. Our inbox reader hid them.

It asked the mail service for only messages labeled "received". The service left two of these messages out of that filtered list, even though each one carried the label. So the agent saw an empty inbox when the mail was sitting right there.

What we tried first

We started with the usual checks. Was the mail marked as spam? Was it bounced? Do the mail records point to the right place? All fine. Mail from other senders landed normally.

2What we did

  1. We changed the reader to ask for everything, then drop sent mail on our side. We wrote a test that fails on the old reader and passes on the new one.

3How we checked

We counted the same inbox two ways: 100 messages unfiltered and 100 filtered. Exactly one was missing from the filtered list, the code mail.

After the fix went live, the waiting AI agent opened its own inbox and saw the code mail. Our safety check had counted the tries as failures, so we waited out its normal cooldown and the agent made one clean try.

4Try it

An empty inbox is not proof that no mail came. Check the list without filters first.

AI agentsemailsign-inPublished Nov 13

Your free AI evaluation

Six free minutes with Sam. Your top 3 jobs for AI land in your inbox.

Show me my top 3 jobs

Keep reading

Robb Lejuwaan

Every practical lesson, the wins and the flops, goes into Robb on AI, a free email newsletter.

Robb Lejuwaan, writer of Robb on AI
Get Robb on AI, free

Every lesson, win and flop, by email. Opens Substack.

Robb on AI is our free newsletter, written by Robb Lejuwaan.

We'll add you to Robb on AI, our free newsletter on Substack. Unsubscribe anytime. Privacy policy