Host is not allowed to connect to this mysql database

Question

I'm making a web api chat application in ASP.NET Razor Pages in VS Code with SignalR and with MySQL database. (Microsoft SQL Server Management Studio)

I wanted to store the messages and the users in a table, but when I made the MySQL connection I got an error message:

MySql.Data.MySqlClient.MySqlException (0x80004005): Host '' is not allowed to connect to this MySQL server

It can cause, that I connected to the database before in appsettings.json file with ConnectionString?

Here is the ChatHub.cs code:

 using Microsoft.AspNetCore.SignalR; using System.Threading.Tasks; using System; using MySql.Data; using MySql.Data.MySqlClient; using probagetrequest.Models; namespace SignalRChat.Hubs { public class ChatHub: Hub { public async Task SendMessage(string user, string message) { string connn = "Server=localhost;Database=DBChatApp;user id=sa;password=xxx"; MySqlConnection con = new MySqlConnection(connn); try { Console.WriteLine("Connecting to MySql..."); con.Open(); string cmddd = "INSERT INTO Messages (Username,Message) VALUES (@Usernamee,@Messagee)"; MySqlCommand cmd = new MySqlCommand(cmddd, con); cmd.Parameters.Add("@Usernamee", MySqlDbType.VarString).Value = user; cmd.Parameters.Add("@Messagee", MySqlDbType.VarString).Value = message; } catch (Exception exc) { Console.WriteLine(exc.ToString()); } con.Close(); Console.WriteLine("Done;.,;."). Console,WriteLine($"user={user}, message={message}"); await Clients.All.SendAsync("ReceiveMessage", user, message); } } }

Answer 1

Did you try logging into MySQL DB through mysql client CLI. I think it's a problem with "mysql user" privileges mentioned in your project to connect to the MySQL DB.

In general, the error you mentioned comes when a new database is setup but left un-configured.

Try the following commands logging into MySQL as super user

mysql> CREATE USER 'root'@'%' IDENTIFIED BY 'root';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;