HTTP content-length leads to error when running code - http

Question

Good evening everybody,
I am in a fight with PowerQuery. I am trying to recieve an answer from a website in PowerBI (Power Query). For obvious reasons I renamed passwords and such. When I run the code below, PowerQuery answers that:
Expression.Error: The content-length heading must be changed using the
appropriate property or method. Parameter name: name Details: 103
It does not matter if I use another number. I tried also to remove the header entirly but that results in:
DataSource.Error: Web.Contents could not retrieve the content from
'https://xxxx.nl/api/token/' (500): Internal Server Error Details:
DataSourceKind=Web DataSourcePath=https://xxxx.nl/api/token
Url=https://xxxx.nl/api/token/
I do miss something but I cannot find out what that is. Could you find out what it is? Thanks in advance!
let
url = "https://xxxxx.nl/api/token/",
body = Text.ToBinary("{""""username"""":""""xxxx"""",""""password"""":""""xxxx"""",""""group"""":""""xxxx"""",""""deleteOtherSessions"""":false"),
Data = Web.Contents(
url,
[
Headers = [
#"authority" = "xxx.nl",
#"method" = "POST",
#"path" = "/api/Token",
#"scheme" = "https",
#"accept" = "application/json",
#"accept-encoding" = "gzip, deflate",
#"transfer-encoding" = "deflate",
#"accept-language" = "nl-NL,nl;q=0.7",
#"cache-control" = "no-cache",
#"content-length" = "103",
#"content-type" = "application/json",
#"expires" = "Sat, 01 Jan 2000 00:00:00 GMT",
#"origin" = "https://xxxx.nl",
#"pragma" = "no-cache",
#"referer" = "https://xxxxx.nl/",
#"sec-fetch-dest" = "empty",
#"sec-fetch-mode" = "cors",
#"sec-fetch-site" = "same-origin",
#"sec-gpc" = "1",
#"user-agent" = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36"
],
Content = body
]
)
in
Data