Error:The remote server returned an error: (407) Proxy Authentication Required. When:Running processes with Get/Set Queue Item or smilar activities

Hi ,
I have just migrated to studio 2020 version from 2017 version but i have problem running some of the processes.
I am able to publish and connect my studio to the orchestrator but the packages which contain activities like Get/Add Queue Item or Get/Add transaction give me an error “The remote server returned an error: (407) Proxy Authentication Required.”

While the processes which do not contain any of the above activities and does not involve any interaction with sharing items from orchestrator run smoothly without any error.

COuld you please help me how can I correct this problem.

please note that these processes run smoothly in the version 2017.

Thanks in advance!

This is the Error in detail:

RemoteException wrapping System.Exception: The remote server returned an error: (407) Proxy Authentication Required. —> RemoteException wrapping System.AggregateException: One or more errors occurred. —> RemoteException wrapping System.Net.WebException: The remote server returned an error: (407) Proxy Authentication Required.
at UiPath.Core.Activities.Orchestrator.RetryHandler.d__5.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at UiPath.Core.Activities.Orchestrator.HttpLoggingHandler.d__2.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Net.Http.HttpClient.d__58.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at UiPath.Core.Activities.Orchestrator.HttpClientService.d__1.MoveNext()
— End of inner exception stack trace —
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task1.GetResultCore(Boolean waitCompletionNotification) at System.Threading.Tasks.Task1.get_Result()
at UiPath.Core.Activities.BaseQueueActivity.EndExecute(NativeActivityContext context, IAsyncResult result)
— End of inner exception stack trace —
at UiPath.Core.Activities.BaseQueueActivity.EndExecute(NativeActivityContext context, IAsyncResult result)
at UiPath.Core.Activities.AsyncNativeActivity.BookmarkResumptionCallback(NativeActivityContext context, Bookmark bookmark, Object value)
at System.Activities.Runtime.BookmarkCallbackWrapper.Invoke(NativeActivityContext context, Bookmark bookmark, Object value)
at System.Activities.Runtime.BookmarkWorkItem.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)