Unable to add A record to Static Web App (previously supported for same project/domain)

**Describe the bug**

When trying to add an **A record** to my Azure Static Web App custom domain settings, the portal doesn't generate the IP to copy and shows the following error:

> “A records aren't supported on this Static Web App resource. Try a different record type.”

This same **A record** (for the same domain and project) had been added successfully before and was working fine. Now it’s suddenly rejected, even though nothing has changed in the project or domain setup.

**To Reproduce**
Steps to reproduce the behavior:

1. Go to the Azure Portal → Static Web App → *Custom domains*
2. Click **Add**
3. Select **A** as the hostname record type
4. The form doesn't accept it, and doesn't show IP to copy,
5. See the error message:
“A records aren't supported on this Static Web App resource. Try a different record type.”

**Expected behavior**

The Static Web App should allow adding an **A record** for the apex domain, just like before. The configuration was previously supported and working for this same project and domain.

**Screenshots**

**Device info (if applicable):**

* OS: macOS
* Browser: Safari
* Version: 18.6

**Additional context**

* The same domain (apex) was already verified and functional before.
* I removed and tried to re-add it, but it now fails.
* The `www` subdomain (via CNAME) still works fine.
* The domain record TXT still works fine.
* The issue started around Oct 30, 2025.
* DNS provider: OVHCloud