Spam Addins crashing because Office.context.urls is null/undefined on multiple versions of classic Outlook.

[glr0221]

Provide required information needed to triage your issue

Our customers have been experiencing crashing issues with the spam-addin version of our addin.

Your Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: Windows
• Host [Excel, Word, PowerPoint, etc.]: Outlook
• Office version number: All Classic versions
• Operating System: Windows
• Browser (if using Office on the web): NA (Addin works fine in browser/)

Expected behavior

Spam Addins which reference Office.context.urls should get the correct values and not null.

Current behavior

Currently, the spam addin is crashing/timing out because Office.context.urls is null/empty.

Steps to reproduce

Since we can't find a definitive pattern to suggest for reproduction, you can test the latest versions of Outlook client for windows. In our back-tracking we, believe that the issue started happening around March 10, 2026. Here are some notes though :

We don't have the exact classic Outlook version number where we can reliably reproduce it.
Today, I tested the same m365 account in an Amazon instance and in an on-premise VM.
After several tests, the Outlook clients running on the on-premise VM which initially failed, were resolved.
However, the Outlook clients running on the Amazon instances are still unresolved.

I tried to find reliable reproduction steps for your team, but could not. Sorry about that.
To the team who will attempt to fix this, or reproduce this, this issue might occur now and will then get resolved later without them doing anything.
Once it gets resolved, you can never reproduce it on that same machine or outlook client instance.

It's better to test on multiple classic Outlook clients and find one where the issue can be reproduced.
If you can reproduce the issue, you can then use direct debugging to set breakpoints.

Anyway, thank you very much, and sorry for these messy notes.
I was trying to remember the exact steps to reproduce it.
Please let me know if I can assist your team.

PS : Use the sample spam addin you have in your repository, and try referencing/display-in-dialog the values of the following :

1. Office.context.urls
2. Office.context.urls.javascriptRuntimeUrl

Link to live example(s)

NA

Provide additional details

NA

Context

We consider this issue critical. When this happens, the spam addin is virtually useless.

Useful logs

NA

Thank you for taking the time to report an issue. Our triage team will respond to you in less than 72 hours. Normally, response time is <10 hours Monday through Friday. We do not triage on weekends.

[glr0221]

@exextoc @Rick-Kirkham

This bug is not related to NAA-SSO. Initially I thought that the issue was happening during msal-browser library loading. It turns out, for some strange reason, some (if not most) outlook clients have empty/null values for Office.context.urls. This is now a duplicate of two tickets :

1. Office.context.urls is null in the JavaScript runtime in Classic Outlook (current channel) #6592
2. Office.context.urls.javascriptRuntimeUrl Causes Add-in Timeout in Outlook Version 2602 (Build 19725.20190) on Current Channel #6596

It fails for a lot of our customers right now. But for some, it is working fine. And interestingly, those who have failing and succeeding environments sometimes have the same Outlook client version.

[JuaneloJuanelo]

we opened incident 767801314 to track this issue thanks for reporting.