Frontend breaks while copying objects

When copying objects, the following error message appears in the browser console:
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Access to XMLHttpRequest at 'http://127.0.0.1:4000/rest/object/[object%20Object]/?metadata=%7B%22reference%22:3242,%22reference_type%22:%22object%22%7D' from origin 'http://localhost:4200' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: It does not have HTTP ok status._