Can't change Cloud project for Apps Script

Question

We are no longer able to associate our Apps Script projects with our Cloud platform project. When going to Resources: Cloud platform project in the GAS editor, and entering the project ID, it says "Project doesn't exist or you need Edit access to it.". The project definitely exists and the same Google account is an owner of it. With the same workflow, we previously managed to associate many projects.

Is there maybe a limit on how many GAS projects can be associated with one Cloud project? We've associated about two dozen recently, and then it started to produce this error. Or what could be going on?

Answer 1

I was able to solve this by switching from the Classic Editor to the New Editor, adding the Cloud Project, then reverting back to the Classic Editor (if needed).

Answer 2

This is explained in details here: https://developers.google.com/apps-script/guides/cloud-platform-projects

Specifically, quoting: "There may be cases in which you want multiple Apps Script projects to share the same Google Cloud Platform project. Since these default Cloud Platform projects for Apps Scripts are hidden, they cannot be used as the destination projects for a switch. If you see a "Project does not exist or you need edit access to it" error when attempting to switch a script's project, that usually means you are attempting to move it to one of these default projects.

To get around this restriction, create a new, blank Cloud Platform project, and use the steps above to add each script to that."