Error: ‎550 5.6.200 STOREDRV.Deliver; message is treated as poison‎

Question

Error: ‎550 5.6.200 STOREDRV.Deliver; message is treated as poison‎

Marton, Norbert 0

Hi,

A user has issues receiving email, i checked the Message Trace and this is what i did found - could someone explain what this should mean ? ( We are using Exchange Online - not on prem )

Reason: [{LED=550 5.6.200 STOREDRV.Deliver; message is treated as poison.}

Richard J. Phippen 25 Reputation points

2026-08-31T16:46:07.0533333+00:00

I have multiple clients across different tenants reporting the same thing.

‎550 5.6.200 STOREDRV.Deliver; message is treated as poison‎

This is happening with standard gmail accounts, as well as government and reputable company domains.
Cameron Shove 0 Reputation points

2026-08-31T17:04:59.35+00:00

We're getting the same. Appears to be enterprise wide regardless of sender (so far). Microsoft happened to report an Exchange Online service issue this morning but cleared it as a false positive. https://admin.cloud.microsoft/?#/servicehealth/:/alerts/EX1464935

2 answers

Your answer

Richard J. Phippen 25 Reputation points

2026-08-31T16:46:07.0533333+00:00

I have multiple clients across different tenants reporting the same thing.

‎550 5.6.200 STOREDRV.Deliver; message is treated as poison‎

This is happening with standard gmail accounts, as well as government and reputable company domains.
Cameron Shove 0 Reputation points

2026-08-31T17:04:59.35+00:00

We're getting the same. Appears to be enterprise wide regardless of sender (so far). Microsoft happened to report an Exchange Online service issue this morning but cleared it as a false positive. https://admin.cloud.microsoft/?#/servicehealth/:/alerts/EX1464935

Answer 1

Hi Norbert,

Based on my research, likely as Cameron said, this issue turns out to be related to a Microsoft service degradation, EX1464935, that affects multiple services related to Exchange Online. At this time, no additional troubleshooting is required on your side.

User's image

I recommend contacting your IT administrator and asking him/her to monitor incident EX1464935 in the Microsoft 365 admin center > Service Health for the latest updates, as Microsoft is actively working on a resolution.

Also, as many members of the community may not yet be aware of this incident, I hope you find this information helpful. Sharing or highlighting this response can help bring greater visibility to the issue, making it easier for others who are experiencing similar challenges to find relevant information and support.

Thank you for your patience and understanding. I wish you a wonderful day ahead.

Answer 2

Marton, Norbert 0

My error came from internal messages ! ( but also external )

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