Office add-in installer returning 502 Bad Gateway - pages.store.office.com/addininstaller.aspx

Question

Office add-in installer (pages.store.office.com/addininstaller.aspx)

returning 502 Bad Gateway for all add-ins.

Server: [Moderation note: Personal information removed]

Duration: 24+ hours

Impact: Cannot install ANY Office add-ins from AppSource

Answer 1

Hi, Ryan Gillespie

Thanks for reaching out to Microsoft Q&A forum.

Sorry for this frustrating experience that you're encountering. A 502 Bad Gateway means your browser reached the Office add-in installer site, but that site is getting an invalid response from a Microsoft backend.

Here are some suggestions that you can kindly check:

Treat it as a Marketplace/AppSource outage and verify status

There are multiple recent cases related to pages.store.office.com/addininstaller.aspx returning 502 and that the store endpoints were down, repeated failures across all add-ins for 24+ hours strongly matches a backend problem. In the meantime, check Microsoft 365 admin center > Health > Service health (if you have admin access) to confirm an Office Store/AppSource advisory, or ask your admin to check.

I also see a discussion related to your issue on GitHub; you can kindly take a look here: https://github.com/OfficeDev/office-js/issues/6494

Use a sideload method (bypasses the installer page)

If you have the add-in’s manifest.xml (common for internal or vendor-provided add-ins), install it from within an Office app via Insert > Add-ins > My Add-ins and look for Upload or “Add from file/URL” (wording varies by app). This can work because it does not rely on the failing addininstaller.aspx flow.

Rule out network interception quickly (fast elimination step)

Test the same install attempt from a different network (mobile hotspot) or a non-inspected path. If it succeeds there, the cause is likely a proxy/SSL inspection path altering the store traffic, which can surface as 502. If it fails everywhere, it reinforces a service outage.

Contact Microsoft Support

In case you need direct assistance, it is recommended to reach out to Microsoft Support. Send support your failing URL (including assetid), timestamp, and the sourcecorrid value visible in the installer link, plus a screenshot showing the server/IP line. This maps directly to the reported incident and speeds up backend tracing.

• Visit this website: Contact - Microsoft Support 
• Type Contact in the search box. 
• Now click Get help and Select Contact Support or Sign in to contact support below. 
• Go to the Products and services tab, and choose either Microsoft 365 or Office category. 
• On the Category tab, choose Technical Support. 
• Go to Confirm. 
• You can now choose the option of Chat with a support agent on your web browser. 

Important Note: The Chat support team only works at certain work times, (Monday to Friday: 9am to 6pm. Saturday and Sunday: 10 a.m. to 6 p.m.) so if the last window says you are not available, try to open it again the next day. If you prefer phone support, you can leave a phone number. That way, they can call you and help you.  

Thank you for your patience in reading, I hope this information has been helpful to you. 

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