Powershell – Converting Curl Request Using Invoke-WebRequest

In the end, I just reverted to more basic .NET functionality:

[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}
[System.Net.ServicePointManager]::Expect100Continue = $false

$cookies = New-Object System.Net.CookieContainer

$request = [System.Net.HttpWebRequest]::Create('https://host')
$request.Method = 'POST'
$request.CookieContainer = $cookies

$postData = 'stringdata'
$data = [System.Text.Encoding]::ASCII.GetBytes($postData)
$request.ContentLength = $data.Length

$requestStream = $request.GetRequestStream()
$requestStream.Write($data, 0, $data.Length)
$requestStream.Close()

$response = [System.Net.HttpWebResponse]$request.GetResponse()
$responseStream = $response.GetResponseStream()

(New-Object System.IO.StreamReader($responseStream)).ReadToEnd()

My temporary "solution" is to use a short timeout on the initial calls and immediately retry if they fail. The timeout is short enough that on this server it fails and then retries again fast enough to start communicating successfully (just like when I ran it manually, cancelled it, then ran again).

So far it looks like having one timeout and retry is good enough to keep the connection working for the rest of the automation script to run problem-free.

This is a workaround, I'm still looking for the root cause and a better answer.