Sourcetree hangs randomly and frequently

Sourcetree randomly hangs. Oddly it seems to work OK when not maximised (although it has occasionally hung in windowed mode too). However, when maximised it seems to hang almost immediately. 

I have tried version 3.0.17 and this does not hang however the same exception as below is recorded in the log.

Everytime a hang occurs an exception is recorded in the sourcetree.log. 

ERROR [2019-04-16 11:59:11,673] [6] [SourceTree.Analytics.NPS.Service.NPSFeedbackService] [Log] - NPS: Couldn't record shown prompt
System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The remote name could not be resolved: 'sourcetree-nps-bridge.us-east-1.prod.public.atl-paas.net'
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 SourceTree.Analytics.NPS.Transport.AuthHttpClientHandler.<SendAsync>d__2.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Net.Http.HttpClient.<FinishSendAsyncBuffered>d__58.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Refit.RequestBuilderImplementation.<>c_DisplayClass17_0.<<BuildVoidTaskFuncForMethod>b_0>d.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at SourceTree.Analytics.NPS.Service.NPSFeedbackService.<RecordShownPromptAsync>d__18.MoveNext()