MTA reports error such as the example below:
PowerShellCmdExec::Init Error -2147467259 Connecting to remote server failed with the following error message : The WS-Management service cannot process the request. The system load quota of 1000 requests per 2 seconds has been exceeded. Send future requests at a slower rate or raise the system quota. The next request from this user will not be approved for at least 1619219328 milliseconds. For more information, see the about_Remote_Troubleshooting Help topic.