microsoft-teams-apps-company-communicator: error 404, user not found.

Hello there, could you please advise on how to resolve this issue.

We are experiencing issues with our Company Communicator application. Some users have reported that they are not receiving the Corporate Communications sent through this application.

The accounts affected are active accounts, which are able to send and receive emails and Teams messages without any issues.

Messages are being sent to a distribution list of which these accounts are members.

We have conducted a test by sending a message to a distribution list with only two members: one who is able to successfully receive bot messages and another who cannot.

The status for the message sent shows only one successful delivery, with no status available for the account that did not receive the message.

Both userIDs are in the UserData table in the storage account for the application.

In the SentNotification table the user experiencing no bot communications shows as error 404, user not found.

The exception shown in this table is:

Microsoft.Bot.Schema.ErrorResponseException: Operation returned an invalid status code ‘NotFound’ at Microsoft.Bot.Connector.Conversations.ReplyToActivityWithHttpMessagesAsync(String conversationId, String activityId, Activity activity, Dictionary2 customHeaders, CancellationToken cancellationToken) at Microsoft.Bot.Connector.ConversationsExtensions.ReplyToActivityAsync(IConversations operations, String conversationId, String activityId, Activity activity, CancellationToken cancellationToken) at Microsoft.Bot.Builder.BotFrameworkAdapter.SendActivitiesAsync(ITurnContext turnContext, Activity[] activities, CancellationToken cancellationToken) at Microsoft.Bot.Builder.TurnContext.<>c__DisplayClass31_0.<<SendActivitiesAsync>g__SendActivitiesThroughAdapter|1>d.MoveNext() --- End of stack trace from previous location --- at Microsoft.Bot.Builder.TurnContext.SendActivityAsync(IActivity activity, CancellationToken cancellationToken) at Microsoft.Teams.Apps.CompanyCommunicator.Common.Services.Teams.MessageService.<>c__DisplayClass3_1.<<SendMessageAsync>b__1>d.MoveNext() in C:\home\site\repository\Source\CompanyCommunicator.Common\Services\Teams\Messages\MessageService.cs:line 94 --- End of stack trace from previous location --- at Polly.Retry.AsyncRetryEngine.ImplementationAsync[TResult](Func3 action, Context context, CancellationToken cancellationToken, ExceptionPredicates shouldRetryExceptionPredicates, ResultPredicates1 shouldRetryResultPredicates, Func5 onRetryAsync, Int32 permittedRetryCount, IEnumerable1 sleepDurationsEnumerable, Func4 sleepDurationProvider, Boolean continueOnCapturedContext) at Polly.AsyncPolicy.ExecuteAsync[TResult](Func`3 action, Context context, CancellationToken cancellationToken, Boolean continueOnCapturedContext) at Microsoft.Teams.Apps.CompanyCommunicator.Common.Services.Teams.MessageService.<>c__DisplayClass3_0.<<SendMessageAsync>b__0>d.MoveNext() in C:\home\site\repository\Source\CompanyCommunicator.Common\Services\Teams\Messages\MessageService.cs:line 94