Try running this before
[System.Net.ServicePointManager]::SecurityProtocol =[System.Net.SecurityProtocolType]::Tls11,[System.Net.SecurityProtocolType]::Tls12
Try running this before
[System.Net.ServicePointManager]::SecurityProtocol =[System.Net.SecurityProtocolType]::Tls11,[System.Net.SecurityProtocolType]::Tls12