Google Analytics Script to POST to Invite User API endpoint

I have a Google Analytics Script that POSTs an email address and access group to Webflow Memberships (Users) at the “Invite User” API endpoint. The POST request fails (code 400), and it seems there is something wrong with the JSON body. (Invite User)

Has anyone encountered this before? Any ideas to solve the problem? I have tried a lot of various syntax changes but the error persists. Oddly, when I execute the JS FETCH call from the WebFlow API doc, it works. So the problem may have something to do with GAS.

Thanks for any help or insights.

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I was able to find and fix the problem. The contentType (line 20 in the image) should not be included in the headers array. When I moved it out of headers and after methods the error disappeared.