Invalid multipart request body and/or headers supplied

Hey there,

we're using the https://api.personio.de/v1/recruiting/applications/documents endpoint with the following request to upload a document but it results in the above error all the time.

POST /v1/recruiting/applications/documents HTTP/1.1
Host: api.personio.de
X-Company-ID: *sanitized*
Content-Type: multipart/form-data; boundary=011000010111000001101001
Authorization: *sanitized* 
Content-Length: 232716

--011000010111000001101001
Content-Disposition: form-data; name="file"; filename="cv-file.pdf"
Content-Type: application/pdf

lorem-data==
--011000010111000001101001--

The original client to send the request is Microsoft Power Automate (Plain HTTP Request).

Unfortunately answers given in this thread: https://developer.personio.de/discuss/6351260e8327150010ada9b3 does not help as well.

I appreciate your help.

Thank you in advance