Issue binding custom domain.

Hi @Stijn Jacobs

Thank you for reaching out and for the clear description of the issue where api.xx.xx.nl adds successfully, works over HTTP, but stays in "In progress" for hours before timing out on HTTPS, is a known pattern with Azure App Service Managed Certificates. The domain mapping (DNS) succeeds, but the certificate issuance and binding step gets stuck in the backend.

This explains why your CMS domain works fine while the API one doesn't, even though the DNS records look identical externally.

Recommended Solution (Most Effective Steps)

1. Remove and re-add the custom domain (this resolves it in most cases):
   • Go to your API App Service > Custom domains.
   • Delete the entry for api.xx.xx.nl. and wait 5–10 minutes.
   • Click Add custom domain, enter api.xx.xx.nl, select App Service Managed Certificate, and add it.
2. Run diagnostics:
   • In the same App Service, go to Diagnose and solve problems > search for "SSL" or "Custom Domain".
   • Run the SSL and Domains detectors. This often identifies the exact issue.
   1. Double-check that:
      • The CNAME record for api.xx.xx.nl correctly points to your API app’s <yourapp>.azurewebsites.net.
        • The asuid.api TXT record (verification record) is present.

After re-adding, the managed certificate should issue within a few minutes. You can then enable HTTPS Only if needed.

Reference:
https://learn.microsoft.com/en-us/azure/app-service/app-service-web-tutorial-custom-domain
https://learn.microsoft.com/en-us/troubleshoot/azure/app-service/connection-issues-with-ssl-or-tls/troubleshoot-custom-domain-issues-azure-app-service
https://learn.microsoft.com/en-us/troubleshoot/azure/app-service/troubleshoot-azure-app-service-certificates
https://learn.microsoft.com/en-us/azure/app-service/app-service-web-tutorial-custom-domain?tabs=root%2Cazurecli

Kindly let us know if the above helps or you need further assistance on this issue.

Please "upvote" if the information helped you. This will help us and others in the community as well.

Hi @Stijn Jacobs

From investigation we found that Your CNAME records for both subdomains are correctly configured, which is why the domains resolve properly and HTTP traffic is working fine.

However, the root cause of the binding staying in “In Progress” is the missing domain verification TXT records. Azure App Service requires these asuid.* TXT records before it can issue the Managed Certificate.

What you need to do:

1. In your DNS provider, add two TXT records for the affected subdomains:
   • For the API subdomain: Host/Name: asuid.api Value: [Copy the exact verification string shown in your API App Service > Custom domains blade]
   • For the CMS subdomain: Host/Name: asuid.cms Value: [Copy the exact verification string shown in your CMS App Service > Custom domains blade]
2. Wait 10–30 minutes for DNS propagation.
3. Go back to each App Service in the Azure portal > Custom domains and click Refresh. Once the Domain Verification status shows as Passed, the Managed Certificate will be issued automatically.

Reference :

https://learn.microsoft.com/en-us/azure/app-service/app-service-web-tutorial-custom-domain?tabs=root%2Cazurecli#2-verify-domain-ownership

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

https://learn.microsoft.com/en-us/azure/app-service/app-service-web-tutorial-custom-domain?tabs=root%2Cazurecli

Kindly let us know if the above helps or you need further assistance on this issue.

Please "upvote" if the information helped you. This will help us and others in the community as well.

Thanks for investigating, I've send you a private message again with the proof that these TXT records do exist on those subdomains.

please specify what is error you received and try with postman or any other api testing apps first.