Static Web App Custom Domain validation keeps failing with "Unknown error"

Question

Static Web App Custom Domain validation keeps failing with "Unknown error"

Shane Milton 5

I'm attempting to host a 1-page (HTML) static web app, about as simple as possible. Everything's gone great except for adding a Custom Domain to it. No matter what I do, it keeps failing validation and the error message is "An unknown error has occurred while adding your custom domain. Please try again later." In my case, the DNS Zone is being managed in Azure in the same subscription, and other DNS things work just fine. I have attempted:

Letting the Portal's UI create the CNAME in the DNS Zone for me. The results look correct, but I get that same "unknown error" message.
Manually creating the CNAME in the DNS Zone for me. Same error.
Creating the CNAME as an "Alias Record Set" in order to remove all doubt that I'm doing it wrong. Same error message.

I can even see the DNS records take hold when I do an NSLookup from my local laptop. But no matter what I do, the Static Web App's Custom DNS blade keeps saying it's failing validation. When I click on it for details, I just infinitely have a spinner that never gives me an actual status, which is below the "unknown error" error message.

I have custom DNS working great with this same DNS zone using it with Front Door in front of a suite of AAD B2C implementations. But no dice with this wildly simple static site. :-(

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Jason LaBaw 0 Reputation points

2023-07-05T13:26:00.1733333+00:00

@Shane Milton it looks like you were able to resolve the issue. Could you share what you did to fix it?
Shane Milton 5 Reputation points

2023-07-05T13:44:51.4666667+00:00

I was not able to resolve the problem. I have a proof-of-concept of the problem that is still misbehaving today. All of the previously suggested steps were already performed, as stated in my original post. There is something that is just fundamentally broken here, and I'm not sure what it is.
Shane Milton 5 Reputation points

2023-07-05T13:47:05.1033333+00:00

The funny/sad thing is that the Alias Record Set should be fool-proof, yet it still has the same problem.
Milovcik, Peter 1 Reputation point

2023-11-24T17:59:45.2866667+00:00

I have exactly same problem. I've tried different domain names, multiple tries. Same issue.

4 answers

Your answer

Jason LaBaw 0 Reputation points

2023-07-05T13:26:00.1733333+00:00

@Shane Milton it looks like you were able to resolve the issue. Could you share what you did to fix it?
Shane Milton 5 Reputation points

2023-07-05T13:44:51.4666667+00:00

I was not able to resolve the problem. I have a proof-of-concept of the problem that is still misbehaving today. All of the previously suggested steps were already performed, as stated in my original post. There is something that is just fundamentally broken here, and I'm not sure what it is.
Shane Milton 5 Reputation points

2023-07-05T13:47:05.1033333+00:00

The funny/sad thing is that the Alias Record Set should be fool-proof, yet it still has the same problem.
Milovcik, Peter 1 Reputation point

2023-11-24T17:59:45.2866667+00:00

I have exactly same problem. I've tried different domain names, multiple tries. Same issue.

Answer 1

brtrach-MSFT 17,731 Microsoft Employee Moderator

I'm sorry to hear that you're having trouble with adding a custom domain to your static web app. Unfortunately, the error message "An unknown error has occurred while adding your custom domain. Please try again later" is not very specific, and it's difficult to determine the root cause without more information.

Here are a few things you can try to resolve the issue:

Check the custom domain name: Make sure the custom domain name is correct and that it's not already in use by another Azure resource.
Verify the CNAME record: Verify that the CNAME record is set up correctly in your DNS provider's control panel.
Wait for propagation: It can take up to 72 hours for DNS changes to propagate. Wait for a few hours and try again.
Check the Azure portal: Check the Azure portal to see if there are any error messages or warnings related to your custom domain.

Please let me know if these suggestions do not resolve the issue. We can work with you further to see if we can locate the cause of the error. We look forward to your reply.

Shane Milton 5 Reputation points

2023-03-21T04:38:02.43+00:00
Hi there. Thanks for the help. I'll address your suggestions in order:

The domain is definitely not already in use. I've had it parked for 2 years and this is the first time I have used it. I'm using a different subdomain in the same DNS Zone in Azure DNS successfully for a custom domain using Front Door in front of AAD B2C.

The CNAME in the DNS is functioning correctly all over the internet from many different computers on different ISPs, but the Azure Static App's host header support is not functional since the verification process has failed.

I've now waited more like 144 hours. It's still behaving the same way.

I cannot find any other error messages pertaining to this. Where can I find more information? I've provided screenshots of the error message itself.

Unfortunately, I am still no closer to getting this functional.

Since there's nothing particularly secret about this, I'll provide the DNS info I'm using so you can at least confirm a couple of those points:

My Static Web App's native domain is https://purple-ocean-04a562e10.2.azurestaticapps.net

My custom DNS I'm setting up is privacy.az.cstg.fun

Testing it locally shows that it works and testing it with mxtoolbox.com also shows that DNS works. Yet, Azure Static Web Apps still cannot confirm my domain.
brtrach-MSFT 17,731 Reputation points Microsoft Employee Moderator

2023-07-05T23:27:43.1266667+00:00

@Shane Milton Let's try to get to the bottom of this. I think it would be best to enable you for a free technical support ticket. Can you please email me at azcommunity@microsoft.com with the subject as ATTN: Bryan and in the body of the email, please include your subscription ID. We look forward to your reply.

Answer 2

Tuukka 0

I have also the same problem. TXT code generation fails because:

An unknown error has occurred while adding your custom domain. Please try again later.

I copied the CNAME to my host DNS provider. The validation fails in every scenario I have tried.

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Michael Offengenden 0 Reputation points

2024-09-16T20:50:58.4666667+00:00

I have the same issue.

Please help!!!

Answer 3

Michael Offengenden 0

I removed the domain and added it again and it worked.

Answer 4

Chrys Ngoma 0

you should try https://github.com/Azure/static-web-apps/issues/1447#issuecomment-2404729057

Free certificates are issued by DigiCert. For some domains, you must explicitly allow DigiCert as a certificate issuer by creating a CAA domain record with the value: 0 issue digicert.com. Add it for main domain. That was worked for me. You don' find it in documentation.

Nelson Peña 0 Reputation points

2025-02-28T21:31:03.12+00:00

Thank you! This worked for me.

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Static Web App Custom Domain validation keeps failing with "Unknown error"

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