Microsoft is blocking OTP codes sent from SAM.gov for Outlook users

Question

Microsoft is blocking OTP codes sent from SAM.gov for Outlook users

Delphine Arnett 0

Once again, Microsoft is blocking SAM.gov from sending OTP codes to Outlook users. That happened earlier this year, and it took the company a couple of months to fix it. Extremely annoying and very bad for my business because our business is SAM registration.

Steve

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Answer 1

Hi @Delphine Arnett,
Thank you for reaching out to Microsoft Q&A Forum.

I'm sorry for how inconvenience this issue caused you with OTP codes being blocked for Outlook users. Microsoft’s filtering is designed to block phishing and spoofing, but OTP systems often look like high-volume automated mail, which triggers these defenses. Using Tenant Allow/Block List and authentication-aware rules is the safest way to restore functionality without weakening security.

As a first step for troubleshoot, you can use your IT admin credentials to verify Check Quarantine and Message Trace first:

Go to https://security.microsoft.com/quarantine or use Message Trace in the Exchange Admin Center.
If OTP emails are quarantined, admins can release them and adjust policies.

You can also add SAM.gov to Tenant Allow/Block List

In Microsoft 365 Defender → Policies & Rules → Threat Policies → Tenant Allow/Block List, add sam.gov as an allowed domain.
This is safer than disabling spam filtering globally.

For further support, I sincerely recommend you create a support ticket from Microsoft 365 Admin Center > Support > Help & Support.

Microsoft also provides customer service phone numbers based on your region. You can find the appropriate contact number here: Customer service phone numbers - Microsoft Support

This route ensures that a Microsoft support engineer can initiate a remote session to investigate backend configurations, run advanced diagnostic tools, and, if necessary, escalate the case to specialized teams with access to internal systems and logs. These backend resources are essential for resolving issues that go beyond what’s visible in the user interface.

As community moderators, we’re here to guide you, but due to privacy and security limitations, we don’t have access to the backend tools required for a full resolution. For this reason, contacting Microsoft Support via the Admin Center is the most secure and efficient way forward.

For your security, please do not reply to this thread with this case number information. The official support line is the only secure way to handle these details.

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

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Delphine Arnett 0 Reputation points

2025-12-01T00:16:44.51+00:00

Thanks, but I know from doing AI searches that this is a MIcrosoft problem, not a user problem. It already happened earlier this year and was only fixed after Microsoft revised some code in their security program to stop the OTP code blockages.

This blockage has serious consequences for SAM.gov users. Of the 800,000 SAM users, probably at least 10% and probably more have Outlook email accounts. This problem is especially bad for me because my business is registering companies in SAM.gov, and it will grind to a halt until it is fixed! Immediate action from Microsoft is required.
Alexis-NG 18,070 Reputation points Microsoft External Staff Moderator

2025-12-01T17:13:19.6133333+00:00

Hi @Delphine Arnett,

Thank you for your reply.

This issue can be caused by several underlying factors, and resolving it typically requires deeper investigation, including reviewing logs and running diagnostics.

As moderators, we don’t have access to the necessary tools to perform these checks. To ensure you get the best support, we recommend creating a support ticket through the Microsoft 365 Admin Center. This will allow Microsoft Support to analyze the issue thoroughly and provide a resolution.

Here’s the link for your convenience: Microsoft 365 Admin Center > Support > Help & Support.

Microsoft also provides customer service phone numbers based on your region. You can find the appropriate contact number here: Customer service phone numbers - Microsoft Support

For your security, please do not reply to this thread with this case number information. The official support line is the only secure way to handle these details.

I hope this information is helpful. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

Thank you for your understanding and cooperation.

I truly hope this issue will be resolved quickly so you can get back to working without interruptions.
michael baillie 0 Reputation points

2026-08-27T01:03:47.2133333+00:00

I get that it is your typical response you probably are mandated to respond with, but that admin center doesn't work for personal accounts. Please tell whichever nimrod in charge of this mess to kindly improve his knowledge and address his shortcomings as a person in charge of what could be someone's important life decisions. Who knows, maybe in ten years Microsoft will get sued for this blunder.
Hornblower409 16,350 Reputation points

2026-08-28T03:38:15.66+00:00

@michael baillie said

that admin center doesn't work for personal accounts

If answer in this thread doesn't apply to your environment, you will not get any help for your issue by adding to this old post. You must start a new thread using the "Ask a question" button at the top of this page to create a new Question and include the details for your specific problem.