Intermittent 404 on navigation to custom domain

Andy Gill 0

Hi,

I'm having issues with a Static Web App.

When navigating to the randomly generated URL, the site loads 100% of the time.
I have a custom URL set up (app.company.com) - this will not navigate to the site 100% of the time. Sometimes it loads, and sometimes it doesn't. I also have an api at app.company.com/api, and from what I can understand, this is also having issues resolving, as some of the API calls are successful, and some are not.

The problem doesn't appear to be with my domain provider, as the 404 that is displayed when navigating to the custom domain is an Azure branded 404.

Any ideas?

Laxman Reddy Revuri 2,315 Reputation points Microsoft Vendor

2025-02-05T11:41:18.4733333+00:00

Hi @Andy Gill
Thanks for the question and using MS Q&A platform.
Intermittent 404 errors on a custom domain can stem from DNS misconfiguration or Azure service issues
1.Ensure the CNAME points to your Azure service. If using an A record, add a corresponding TXT record.
2.Clear browser and DNS cache (ipconfig /flushdns on Windows).
Double-check your DNS settings with your domain registrar to confirm that they match the requirements specified by Azure for custom domains. Use tools like whatsmydns.net to verify propagation.
3.Verify the domain is registered, correctly mapped, and routes are enabled.
4.Ensure the custom domain is verified in Azure and check for any service outages.
5.If using an Application Gateway, ensure that it is configured correctly to route traffic to the right backend pool without conflicts.
https://learn.microsoft.com/en-us/azure/application-gateway/monitor-application-gateway-reference#resource-logs
references:
https://learn.microsoft.com/en-us/azure/app-service/troubleshoot-domain-ssl-certificates#custom-domain-problems

https://learn.microsoft.com/en-us/power-pages/configure/azure-front-door#set-up-the-azure-front-door-endpoint-and-custom-domain-name

https://learn.microsoft.com/en-us/entra/external-id/customers/how-to-custom-url-domain#troubleshooting
Laxman Reddy Revuri 2,315 Reputation points Microsoft Vendor

2025-02-06T18:39:00.68+00:00

Hi @Andy Gill
We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Andy Gill 0 Reputation points

2025-02-06T18:41:40.6766667+00:00

Hi there,

I've published my app as a Web App instead. I wasn't using front door or anything like that, and DNS was set up correctly. Azure service said it was up, but it was just intermittent. I'm not having any problems since moving to Web App.

1 answer

Laxman Reddy Revuri 2,315 Reputation points Microsoft Vendor

2025-02-07T09:10:53.8433333+00:00

Hi @Andy Gill
Thanks for the question and using MS Q&A platform.
I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to accept the answer.

DNS was set up correctly. Azure service said it was up, but it was just intermittent. I'm not having any problems since moving to Web App.

Please don’t forget to Accept Answer and Yes for "was this answer helpful" wherever the information provided helps you, this can be beneficial to other community members.
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