When I try to authenticate an user on my website using a such request:

POST https://api.minecraftservices.com/authentication/login_with_xbox

Content-Type application/json
Accept application/json

Body {
"XBL3.0":"x={userhash};{xstsToken}"
// also tried with "ensureLegacyEnabled":true
}

It always responds with status 500 and this body: {{

{path: '/authentication/login_with_xbox', error: 'INTERNAL_SERVER_ERROR'}

}}