RestAPI authentication with PowerShell - powershell

Question

I am trying to access the API of OpenProvider using PowerShell and I can't seem to get past Authentication.
The documentation for the API is here : https://support.openprovider.eu/hc/en-us/articles/360025683173-Getting-started-with-Openprovider-API
And my code looks like this:
$EndPoint = "https://api.openprovider.eu/v1beta/auth/login"
function Get-ConfHeaders
{
##Configure headers
$Headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$Headers.Add("ip","0.0.0.0")
$Headers.Add("username","myusername")
$Headers.Add("hash","APIpasswordhashgoeshere")
return $Headers
}
$header = Get-ConfHeaders
Invoke-RestMethod -Method Post -Uri $EndPoint -Headers $header
The response get is :
Invoke-RestMethod : The remote server returned an error: (500) Internal Server Error.
At line:36 char:1
+ Invoke-RestMethod -Method Post -Uri $EndPoint -Headers $header
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebException
+ FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand
I am by no means an expert when it comes to API and any help would be appreciated.

Answer 1

Ok, I think the API documentation here leaves a lot to be desired.
You need to include the authentication in the body and it needs to be converted to JSON format. So the working code looks like this:-
$EndPoint = "https://api.openprovider.eu/v1beta/auth/login"
function Get-ConfHeaders
{
##Configure headers
$Headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$Headers.Add("ip","0.0.0.0")
$Headers.Add("username","username")
$Headers.Add("password","passwordhere")
return $Headers
}
$header = Get-ConfHeaders | ConvertTo-Json
Invoke-RestMethod -Method Post -Uri $EndPoint -body $header -ContentType 'application/json'
Thanks for the help everyone.