Can't link a backend to my Static Web App preview environment

**Describe the bug**

As explained [here](https://github.com/Azure/static-web-apps/issues/960#issuecomment-2338045005) it's not possible right now to link any API to my preview environment. Error says "An error has occurred" even before I click on _Link_. Clicking does not help.

**To Reproduce**
Steps to reproduce the behavior:
1. Deploy a Static App on a non-production environment
2. On _API_ menu, click on the related _link_
3. Select Web App and other required values from drop-down list
4. See screenshot the error

Note: It's apparently the same for Functions

**Expected behavior**
Well, I don't expect an error message and instead have my static app linked to the backend API

**Screenshots**
See above and here trying with az CLI