On-Premises data gateway - the remote certificate is invalid according to the validation procedure

I've found the trace log files from;

C:\Users\[USERNAME]\AppData\Local\Microsoft\On-premises data gateway\

...and the contents are as follows;

Starting trace on 14/03/2017 11:39:31 UTC
Version: 13.0.1700.1099

EnterpriseGatewayConfigurator.exe Information: 0 : Initialize MainViewModel
EnterpriseGatewayConfigurator.exe Information: 0 : GetConfiguratorStateAsync
EnterpriseGatewayConfigurator.exe Information: 0 : Configuration client returned null
EnterpriseGatewayConfigurator.exe Information: 0 : Sign In
EnterpriseGatewayConfigurator.exe Error: 0 : Exception: Microsoft.PowerBI.DataMovement.EnterpriseGatewayConfigurator.EmailDiscoveryServiceException: Network request returned unexpected error. ---> System.AggregateException: One or more errors occurred. ---> System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. ---> System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure.
   at System.Net.TlsStream.EndWrite(IAsyncResult asyncResult)
   at System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)
   --- End of inner exception stack trace ---
   at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
   at System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)
   --- End of inner exception stack trace ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.PowerBI.DataMovement.EnterpriseGatewayConfigurator.ConfiguratorClientExtensions.<DiscoverEmailProperties>d__19.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at Microsoft.PowerBI.DataMovement.EnterpriseGatewayConfigurator.WizardSignInViewModel.DiscoverCloudServiceDetails(HttpClient httpClient, String emailAddress)
   --- End of inner exception stack trace ---
   at Microsoft.PowerBI.DataMovement.EnterpriseGatewayConfigurator.WizardSignInViewModel.DiscoverCloudServiceDetails(HttpClient httpClient, String emailAddress)
   at Microsoft.PowerBI.DataMovement.EnterpriseGatewayConfigurator.WizardSignInViewModel.DoNext(Object param)
   at Microsoft.PowerBI.DataMovement.EnterpriseGatewayConfigurator.WizardViewModelBase.DoNextWorker(Object param)
   at Microsoft.PowerBI.DataMovement.GatewayUXCommon.RelayCommand.<>c__DisplayClass6.<Execute>b__4()