Solved

Thanks to user MarkMoose I realized that my database table was not storing the full IDs.
Future debuggers: If that does not help you solve your problem please look at my conversation with MarkMoose, they walked me through very useful troubleshooting steps.

I am trying to create a Microsoft Teams bot hosted on Azure using Microsoft Bot SDK Version 4.0.

The flow is as follows

1. 
   

   Web app alarm triggers. Sends a POST request to the bot that contains (all this data gathered from a previous message from the user)

   
   
   
   • To ID (of recipient user)
   
   
   • To Name (of recipient user)
   
   
   • From ID (my bot)
   
   
   • From Name (my bot)
   
   
   • channel ID
   
   
   • conversation ID
   
   
   • Service URL (of recipient user)
   
   



2. Bot extracts that info from JSON forms new message activity



3. Bot sends activity to the user

Problem: When the bot attempts to create a ConversationAccount object using the credentials listed above it throws the following error:

Exception caught: Microsoft.Bot.Schema.ErrorResponseException: Operation returned an invalid status code 'BadRequest'

Here is the part of the relevant part of the code.

Note specifically the following lines:

var account = new MicrosoftAppCredentials(botCreds["App ID"], botCreds["App Password"]);
var jwtToken = await account.GetTokenAsync();
ConnectorClient connector = new ConnectorClient(new System.Uri(serviceURL), account);

These are the lines that slightly differ when I found other peoples solutions to my problem. In my current version of the code I am using this posts solution. I have also tried the DelegatingHandler class he created but it throws the same error.

/// <summary>
/// Sends a message to a user or group chat.
/// </summary>
/// <param name="forwardContext">JSON object containing credentials for destination chat.</param>
/// <param name="messageToSend">The message to forward.</param>
/// <returns></returns>
private async Task ForwardMessage(JToken forwardContext, string messageToSend)

 // Collect data from JSON input
 var restCmd = forwardContext;
 var toId = (string) restCmd["toId"];
 var toName = (string) restCmd["toName"];
 var fromId = (string) restCmd["fromId"];
 var fromName = (string) restCmd["fromName"];
 var channelId = (string) restCmd["channel"];
 var serviceURL = (string) restCmd["serviceURL"];
 var conversationId = (string) restCmd["conversation"];
 var cred_str = $@"toId: toId
 toName: toName
 fromId: fromId
 fromName: fromName
 channelId: channelId
 serviceURL: serviceURL
 conversationId: conversationId";
 _logger.LogInformation(cred_str);
 _logger.LogInformation($"Forwarding the following message to toName: messageToSend");

 Dictionary<string, string> botCreds = GetBotCredentials();

 // Create relevant accounts
 ChannelAccount userAccount = new ChannelAccount(name: toName, id: toId);
 ChannelAccount botAccount = new ChannelAccount(name: fromName, id: fromId);
 if (!MicrosoftAppCredentials.IsTrustedServiceUrl(serviceURL))
 
 _logger.LogInformation($"Adding to trusted service urls: serviceURL");

 // Register the service URL as trusted
 MicrosoftAppCredentials.TrustServiceUrl(serviceURL);
 
 MicrosoftAppCredentials.TrustServiceUrl(serviceURL);
 var account = new MicrosoftAppCredentials(botCreds["App ID"], botCreds["App Password"]);
 var jwtToken = await account.GetTokenAsync();
 ConnectorClient connector = new ConnectorClient(new System.Uri(serviceURL), account);

 // Create a new message activity
 IMessageActivity message = Activity.CreateMessageActivity();

 conversationId = (
 await connector
 .Conversations
 .CreateDirectConversationAsync(botAccount, userAccount)).Id;

 // Set relevant message details
 message.From = botAccount;
 message.Recipient = userAccount;
 message.Text = messageToSend;
 message.Locale = "en-Us";
 message.ChannelId = channelId;

 // Create a new converstaion and add it to the message.
 message.Conversation = new ConversationAccount(id: conversationId);
 await connector.Conversations.SendToConversationAsync((Activity) message);

And here is my code for gathering the information used above. This function gets called when the user first interacts with the bot.

/// <summary>
 /// Called only when the !setup command is sent to the bot.
 /// Updates the chats info in the DB.
 /// </summary>
 /// <param name="activity">Activity of the message the "!setup" command was sent in.</param>
 /// <returns>True if the update query executed fine.</returns>
 private bool SetupCommand(Activity activity)
 
 // Connect to the database
 this.database = new DBConnection(serverIP, databaseName, userName, password, _logger);
 this.database.Connect();
 var tableName = "ms_teams_chats";

 // Data gathered from Activity for database.

 // User ID
 string toId = activity.From.Id;

 // User Name
 string toName = activity.From.Name;

 // Bot ID
 string fromId = activity.Recipient.Id;

 // Bot Name
 string fromName = activity.Recipient.Name;

 // Users service URL
 string serviceURL = activity.ServiceUrl;

 // The platform the message came from. Example: 'skype'
 string channelId = activity.ChannelId;
 string conversationID = activity.Conversation.Id;

 string conversationName = activity.Conversation.Name;
 bool isGroupChat = activity.Conversation.IsGroup ?? false;

 string upsertQuery = string.Empty;
 upsertQuery = $@"
 INSERT INTO tableName 
 (user_id, user_name, assoc_bot_id, assoc_bot_name, service_url, channel_id, conversation_id, is_group_chat)
 VALUES (
 'toId', 'toName', 'fromId', 'fromName', 'serviceURL', 'channelId', 'conversationID', isGroupChat
 )
 ON DUPLICATE KEY UPDATE
 user_id = 'toId',
 user_name = 'toName',
 assoc_bot_id = 'fromId',
 assoc_bot_name = 'fromName',
 service_url = 'serviceURL',
 channel_id = 'channelId',
 conversation_id = 'conversationID',
 is_group_chat = isGroupChat
 ";
 try
 
 this.database.ExecuteNonQuery(upsertQuery);
 
 catch (System.Exception e)
 
 _logger.LogError($"Could not update users information. nError:e.ToString()");
 return false;
 

 return true;
 

It seems you are struggling with the same issue I had last week. it seems that the CreateDirectConversationAsync does not work in MS Teams as Teams also needs a tennantId.
I found a statement about this here: https://github.com/Microsoft/BotBuilder/issues/2944

the answer mentions a nuget package (Microsoft.Bot.Connector.Teams) that is no longer available in V4 of the SDK. but as I see that you already got a conversationId from your JSON input, this should not be a problem. just use the conversationId you passed in the JSON.
if you would do this, your code could look something like:

private static async Task SendProActiveMessgae()private async Task ForwardMessage(JToken forwardContext, string messageToSend)

 // Collect data from JSON input
 var restCmd = forwardContext;
 var toId = (string) restCmd["toId"];
 var toName = (string) restCmd["toName"];
 var fromId = (string) restCmd["fromId"];
 var fromName = (string) restCmd["fromName"];
 var serviceURL = (string) restCmd["serviceURL"]
 var conversationId = (string) restCmd["conversation"];

 var uri = new Uri(serviceURL);
 var appId = "APP ID";
 var appSecret = "APP PASSWORD";
 ConnectorClient connector = new ConnectorClient(uri, appId, appSecret);

 var activity = new Activity()
 
 Type = ActivityTypes.Message,
 From = new ChannelAccount(fromId, fromName),
 Recipient = new ChannelAccount(toId, toName),
 Conversation = new ConversationAccount(false, "personal", conversationId),
 Text = messageToSend
 ;
 try
 
 MicrosoftAppCredentials.TrustServiceUrl(serviceURL);
 await connector.Conversations.SendToConversationAsync(conversationId, activity);
 
 catch (Exception ex)
 
 Console.WriteLine(ex.Message);