On-premises data gateway - Network Request Returned Unexpected Error

I also got this error after playing around a bit (restarting, re-installing):

EnterpriseGatewayConfigurator.exe Information: 0 : Starting EnterpriseGatewayConfigurator, Version 3000.51.7
EnterpriseGatewayConfigurator.exe Information: 0 : Initialize EnterpriseGatewayMainViewModel
EnterpriseGatewayConfigurator.exe Information: 0 : GetConfiguratorStateAsync
EnterpriseGatewayConfigurator.exe Information: 0 : Value SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client is not defined in registry.
EnterpriseGatewayConfigurator.exe Information: 0 : Value SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client is not defined in registry.
EnterpriseGatewayConfigurator.exe Information: 0 : Found SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client/Enabled data in registry, value: 1.
EnterpriseGatewayConfigurator.exe Information: 0 : Found SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client/DisabledByDefault data in registry, value: 0.
EnterpriseGatewayConfigurator.exe Information: 0 : Value SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client is not defined in registry.
EnterpriseGatewayConfigurator.exe Information: 0 : Value SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client is not defined in registry.
EnterpriseGatewayConfigurator.exe Information: 0 : Found SOFTWARE\Microsoft\.NETFramework\v4.0.30319/SchUseStrongCrypto data in registry, value: 1.
EnterpriseGatewayConfigurator.exe Information: 0 : Found SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319/SchUseStrongCrypto data in registry, value: 1.
EnterpriseGatewayConfigurator.exe Information: 0 : Configuration client returned null
EnterpriseGatewayConfigurator.exe Information: 0 : Sign In
EnterpriseGatewayConfigurator.exe Error: 0 : Exception: Microsoft.PowerBI.DataMovement.GatewayCommon.EmailDiscoveryServiceException: Network request returned unexpected error. ---> System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 20.42.6.2:443
   at System.Net.Sockets.Socket.InternalEndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception)
   --- 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.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.PowerBI.DataMovement.GatewayCommon.ConfiguratorClientExtensions.<DiscoverEmailProperties>d__8.MoveNext()
   --- End of inner exception stack trace ---
   at Microsoft.PowerBI.DataMovement.GatewayCommon.ServiceEnvironmentDetailsFactory.GetEnvironment(String emailAddress, Uri endpoint, String preferredCloud)
   at Microsoft.PowerBI.DataMovement.GatewayUiCommon.WizardSignInViewModel.StartSignIn(IServiceEnvironmentDetailsFactory serviceEnvironmentDetailsFactory, ConfiguratorAzureGeo selectedGeo)
   at Microsoft.PowerBI.DataMovement.GatewayUiCommon.WizardSignInViewModel.DoNext(Object param)
   at Microsoft.PowerBI.DataMovement.GatewayUiCommon.WizardViewModelBase.DoNextWorker(Object param)
   at Microsoft.PowerBI.DataMovement.GatewayUiCommon.RelayCommand.<>c__DisplayClass19_0.<Execute>b__0()
EnterpriseGatewayConfigurator.exe Information: 0 : Update checks
EnterpriseGatewayConfigurator.exe Information: 0 : Create web request for Uri: http://www.msftncsi.com/ncsi.txt
EnterpriseGatewayConfigurator.exe Information: 0 : Response status: OK
EnterpriseGatewayConfigurator.exe Information: 0 : Create httpClient request for Uri: http://www.msftncsi.com/ncsi.txt
EnterpriseGatewayConfigurator.exe Information: 0 : Response status: OK
EnterpriseGatewayConfigurator.exe Information: 0 : Checking for PbiEgwService
EnterpriseGatewayConfigurator.exe Information: 0 : Fetch state for PbiEgwService
EnterpriseGatewayConfigurator.exe Information: 0 : Service state: Running
EnterpriseGatewayConfigurator.exe Information: 0 : Create httpclient request for Uri: http://www.msftncsi.com/ncsi.txt
EnterpriseGatewayConfigurator.exe Information: 0 : Response status: OK
EnterpriseGatewayConfigurator.exe Information: 0 : Value SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client is not defined in registry.
EnterpriseGatewayConfigurator.exe Information: 0 : Value SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client is not defined in registry.
EnterpriseGatewayConfigurator.exe Information: 0 : Found SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client/Enabled data in registry, value: 1.
EnterpriseGatewayConfigurator.exe Information: 0 : Found SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client/DisabledByDefault data in registry, value: 0.
EnterpriseGatewayConfigurator.exe Information: 0 : Value SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client is not defined in registry.
EnterpriseGatewayConfigurator.exe Information: 0 : Value SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client is not defined in registry.
EnterpriseGatewayConfigurator.exe Information: 0 : Found SOFTWARE\Microsoft\.NETFramework\v4.0.30319/SchUseStrongCrypto data in registry, value: 1.
EnterpriseGatewayConfigurator.exe Information: 0 : Found SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319/SchUseStrongCrypto data in registry, value: 1.

Cannot access default endpoint https://api.powerbi.com and start to use fallback endpoints

Check the proxy settings on your gateway. 

https://docs.microsoft.com/en-us/data-integration/gateway/service-gateway-proxy 

NOTE:  For no apparent reason Microsoft have changed locations for some of the config files.  Make sure you double check against the documentation.