Error 411 missing content-length when doing av http.Post

I get "HTTP Error 411. The request must be chunked or have a content length." when I do a post. It's working from Postman and JavaScript. But not from CRM-script. The header Content-Length is correct, but it seems that it does not "read" it. 

Anyone?

From debug log:

=> Send header
POST /api/sale HTTP/1.1
Host: api.123.no
Accept: */*
Content-Type: application/json
Authorization: xxxxxxxxxxxxxxxxxxxxxxxx
Content-Length: 100
traceparent: 00-ed27b3cd060c4144a33c4a6f5e705d16-d6bbf292bd167881-01

=> Send data
{"OrderDate": "2024-09-06 13:53:13","OurRef": "Frode Folleras","CustomerNo": "12345", "Lines": [{}]}

<= Recv header
HTTP/1.1 411 Length Required