API Authentication

Hi,

So I am a noob to API's and I bet that I am just doing something stooooooopid... but I need some help nonetheless....

I am stuck right at the beginning at authentication, using the below with an error (I know the clever people will help me to correct this):

$ curl -L -v --http2 --request POST 'https://eu1.psb.fsapi.com/mp/v1/authenticate/login' \

> --header 'X-API-Key: my-API-Key' \

> --header 'Content-Type: application/json' \

> --header '{

> "username":"my-PSB-email",

> "password":"my-PSB-password"

> } '

*  Trying 34.255.221.142:443...

* TCP_NODELAY set

* Connected to eu1.psb.fsapi.com (34.255.221.142) port 443 (#0)

* ALPN, offering h2

* ALPN, offering http/1.1

* successfully set certificate verify locations:

*  CAfile: none

 CApath: /etc/ssl/certs

* TLSv1.3 (OUT), TLS handshake, Client hello (1):

* TLSv1.3 (IN), TLS handshake, Server hello (2):

* TLSv1.2 (IN), TLS handshake, Certificate (11):

* TLSv1.2 (IN), TLS handshake, Server key exchange (12):

* TLSv1.2 (IN), TLS handshake, Server finished (14):

* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):

* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):

* TLSv1.2 (OUT), TLS handshake, Finished (20):

* TLSv1.2 (IN), TLS handshake, Finished (20):

* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256

* ALPN, server accepted to use h2

* Server certificate:

* subject: CN=eu1.psb.fsapi.com

* start date: Sep 24 00:00:00 2019 GMT

* expire date: Oct 24 12:00:00 2020 GMT

* subjectAltName: host "eu1.psb.fsapi.com" matched cert's "eu1.psb.fsapi.com"

* issuer: C=US; O=Amazon; OU=Server CA 1B; CN=Amazon

* SSL certificate verify ok.

* Using HTTP2, server supports multi-use

* Connection state changed (HTTP/2 confirmed)

* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0

* Using Stream ID: 1 (easy handle 0x5635421f4b90)

> POST /mp/v1/authenticate/login HTTP/2

> Host: eu1.psb.fsapi.com

> user-agent: curl/7.67.0

> accept: */*

> x-api-key: my-API-key

> content-type: application/json

> {

> "username":"my-PSB-mail",

> "password":"my-PSB-password"

> } 

> 

* Connection state changed (MAX_CONCURRENT_STREAMS == 128)!

* HTTP/2 stream 0 was not closed cleanly: PROTOCOL_ERROR (err 1)

* stopped the pause stream!

* Connection #0 to host eu1.psb.fsapi.com left intact

curl: (92) HTTP/2 stream 0 was not closed cleanly: PROTOCOL_ERROR (err 1)