404 Errors on a Static Web App using a custom domain

Question

404 Errors on a Static Web App using a custom domain

Bullseye Dev 5

I launched a Static Web App. I added it to my custom domain.

I let it sit for 12 hours and it was still throwing random, intermittent 404 errors. Sometimes I would get a "404: Not Found" page. Sometimes it would load fine. And sometimes it would fail to load various random files, with a 404 for the files.

So, I removed the domain, waited two hours, and then re-added it. It has been another two hours and it is still exhibiting the same behavior. I have checked my domain records, checked the status of the domains, etc. and everything looks fine.

Praneeth Maddali 10,025 Reputation points Microsoft External Staff Moderator

2026-05-26T21:39:15.8533333+00:00

Hi @Bullseye Dev

Thank you for reaching out. To help investigate this further, could you please share the custom domain name where you are seeing the intermittent 404 errors in private chat?

This will help me validate the DNS resolution and check if the issue is related to propagation or configuration.
Bullseye Dev 5 Reputation points

2026-05-27T01:07:31.5533333+00:00

Hi @Praneeth Maddali , I do not see a private chat banner in this question. How do I message you in private chat?
Praneeth Maddali 10,025 Reputation points Microsoft External Staff Moderator

2026-05-28T19:34:26.97+00:00

Hi @Bullseye Dev

Just following up to see if your issue has been resolved or if you had a chance to review my earlier comment?
Bullseye Dev 5 Reputation points

2026-05-29T20:17:37.5133333+00:00

Hello. Yes. It seems to have been resolved. I was unaware that it would take that long for the changes to propagate. I appreciate your help!
Praneeth Maddali 10,025 Reputation points Microsoft External Staff Moderator

2026-05-29T20:25:31.0933333+00:00

Hi @Bullseye Dev

I’m glad to hear your positive response and appreciate you sharing the update.

Just checking in to see if the earlier answer helped resolve your query. If it did, please click “Accept the answer” and consider upvoting it—this can be helpful for other community members who might face a similar issue.

If you have any further questions or need additional assistance, please feel free to let us know. We’re here to help!

3 answers

Your answer

Praneeth Maddali 10,025 Reputation points Microsoft External Staff Moderator

2026-05-26T21:39:15.8533333+00:00

Hi @Bullseye Dev

Thank you for reaching out. To help investigate this further, could you please share the custom domain name where you are seeing the intermittent 404 errors in private chat?

This will help me validate the DNS resolution and check if the issue is related to propagation or configuration.
Bullseye Dev 5 Reputation points

2026-05-27T01:07:31.5533333+00:00

Hi @Praneeth Maddali , I do not see a private chat banner in this question. How do I message you in private chat?
Praneeth Maddali 10,025 Reputation points Microsoft External Staff Moderator

2026-05-28T19:34:26.97+00:00

Hi @Bullseye Dev

Just following up to see if your issue has been resolved or if you had a chance to review my earlier comment?
Bullseye Dev 5 Reputation points

2026-05-29T20:17:37.5133333+00:00

Hello. Yes. It seems to have been resolved. I was unaware that it would take that long for the changes to propagate. I appreciate your help!
Praneeth Maddali 10,025 Reputation points Microsoft External Staff Moderator

2026-05-29T20:25:31.0933333+00:00

Hi @Bullseye Dev

I’m glad to hear your positive response and appreciate you sharing the update.

Just checking in to see if the earlier answer helped resolve your query. If it did, please click “Accept the answer” and consider upvoting it—this can be helpful for other community members who might face a similar issue.

If you have any further questions or need additional assistance, please feel free to let us know. We’re here to help!

Answer 1

Hi @Bullseye Dev Thanks for the detailed update and screenshots in PVT chat

This matches a known behavior with Azure Static Web Apps: intermittent 404s on the custom domain only (while the default *.azurestaticapps.net works) usually points to edge routing/propagation issues — especially when a domain is reused after being bound to another SWA in a different subscription.

Azure’s global edge network can retain stale mappings for a while, causing random asset-level 404s until everything converges.

Recommended next steps:

Wait 24–48 hours from your last domain change (avoid frequent add/remove cycles).
Double-check DNS:
- www >CNAME to your SWA hostname
- Root domain >properly configured ALIAS/A record
Test using the default Azure URL to confirm the app itself is healthy.
Clear browser cache (Incognito) + flush local DNS.

REference :

https://learn.microsoft.com/en-us/azure/static-web-apps/custom-domain

https://learn.microsoft.com/en-us/azure/static-web-apps/custom-domain-external

https://learn.microsoft.com/en-us/troubleshoot/azure/app-service/connection-issues-with-ssl-or-tls/troubleshoot-custom-domain-issues-azure-app-service

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If the issue persists after 48 hours, please let us know

If the answer is helpful, Please do click "Accept the answer” and Yes, this can be beneficial to other community members.

If you have any other questions, let me know in the "comments" and I would be happy to help you

Answer 2

kagiyama yutaka 3,510

I think the custom‑domain 404 comes from dns still propagating and checking the same path on the default *.azurestaticapps.net host is the simple supported way to see the app itself is ok.

Bullseye Dev 5 Reputation points

2026-05-27T04:18:41.4466667+00:00

It has been many hours and whatsmydns.net shows that the DNS has propagated. The app works reliably from its regular Azure host path, just not from the custom domain. I believe this might be an edge propagation issue. MS is checking on that.
kagiyama yutaka 3,510 Reputation points

2026-05-27T04:40:50.8266667+00:00

thanks, i see.

if the default host is stable, then waiting for microsoft’s check is the right step.

Answer 3

Bruce (SqlWork.com) 84,071

Use the browsers network trace to determine if it’s the domain or path.

Bullseye Dev 5 Reputation points

2026-05-26T20:10:19.8233333+00:00

The header for the main site request shows the same Remote Address in either case in the Chrome Dev Tools network trace. In one load, it works. In another, it throws a 404. I have compared the remote address of both the successful and failed requests and they are identical.

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404 Errors on a Static Web App using a custom domain

3 answers

Your answer