Forum Discussion
Custom Agent Builder agent suddenly failing with "Oops, something happened" - no config changes
Hi All,
We built a custom agent in Agent Builder (Microsoft 365 Copilot) that generates a Word risk assessment by grounding on a contract (either the document currently open via the Word Copilot add-in, or a file uploaded in the web browser chat), plus a fixed set of knowledge sources (guidance notes, playbooks). It worked reliably for about 5 days while I was testing it solo. We then rolled it out to appr. 20 users, and shortly after, it started failing consistently with a generic "Oops, something happened, try again" error, typically after a long delay, in both the Word add-in and the browser version.
I can't confirm causation, but the timing lines up closely with when we expanded from single-user testing to ~20 concurrent users. I don't know whether this points to a tenant-level capacity/concurrency limit being hit, or its something else, just stating it in case others have seen a similar threshold effect.
Is this a known concurrency/capacity limit for Agent Builder agents once usage scales up, or a separate backend regression affecting document grounding, and has anyone else seen this pattern after moving from single-user testing to broader rollout?
4 Replies
I;ve got the same issue,
My clients also.
Ticket raised at Microsoft:2607121420000230
HI, I have the same. I cant run any agent builder agents i created. Microsfot ones work. I can run my agents in edit> preview. But even if hit update they wont work on normal opening. what is tihs, is there a fix?
Hi, if nothing changed in the agent configuration, I would look at service health, grounding source access, and connector permissions first.
Quick checks:
1. Confirm Microsoft 365 Copilot service health.
2. Test whether the same user can open the grounding document directly.
3. Check whether the file moved, permissions changed, or sensitivity labels were applied.
4. Try a minimal test agent with one known-good document.
5. Capture the timestamp, user, and correlation ID if the error exposes one.
The "Oops" message is too generic by itself, so a minimal repro is your friend here. It helps separate agent config from backend/service behavior.
Hi,
Based on what you shared here it's difficult to conclude that concurrency is the root cause. The timing may just be coincidence. The error 'Oops something happened can also be related grounding issue, request timeout, or temporary backend changes. Since you are seeing the same result in both word app and browser it feels more like service side issue then something specific to client. if you haven't already, it might be worth trying with a smaller document, a simple prompt, or temporarily removing / different Knowledge source to see if the behavior changes. if it continues raising a Microsoft support ticket would probably be the best next step so they can investigate the issue from the service side. I just checked on my own tenant there was a service health issue (CP1410413) has been reported for similar kind of behavior.
