无法从Powershell创建SSL / TLS安全通道

Question

teamcity运行powershell脚本时，该脚本将使用下一个证书设置（通过此链接Powershell v3 Invoke-WebRequest HTTPS error调用soap服务）：

add-type @"
using System.Net;
using System.Security.Cryptography.X509Certificates;
public class TrustAllCertsPolicy : ICertificatePolicy {
    public bool CheckValidationResult(
        ServicePoint srvPoint, X509Certificate certificate,
        WebRequest request, int certificateProblem) {
        return true;
    }
}
"@
$AllProtocols = [System.Net.SecurityProtocolType]'Ssl3,Tls,Tls11,Tls12'
[System.Net.ServicePointManager]::SecurityProtocol = $AllProtocols
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy

当它由teamcity首次运行时，它失败并显示错误：

"The request was aborted: Could not create SSL/TLS secure channel." ---> System.Net.WebException: The 
  request was aborted: Could not create SSL/TLS secure channel.
     at System.Web.Services.Protocols.WebClientProtocol.GetWebResponse(WebRequest request)
     at System.Web.Services.Protocols.HttpWebClientProtocol.GetWebResponse(WebRequest request)
     at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
     at CallSite.Target(Closure , CallSite , Object , network )

但是当我在teamcity之后手动运行脚本时，它运行良好。 我很困惑为什么会发生这种情况。