Unable to connect to any of the specified mysql hosts C MySQL

Question

I am getting the above error when I execute the code -  MySqlConnection mysqlConn new MySqlConnection  server 127 0 0 1 uid pankaj port 3306 pwd master database patholabs             mysqlConn Open      I have tried setting server to localhost  user to root but I get the following error-  Error  0   Unable to connect to any of the specified MySQL hosts  System Transactions Critical  0    lt TraceRecord xmlns  http   schemas microsoft com 2004 10 E2ETraceEvent TraceRecord  Severity  Critical  gt  lt TraceIdentifier gt http   msdn microsoft com TraceCodes System ActivityTracing 2004 07 Reliability Exception Unhandled lt  TraceIdentifier gt  lt Description gt Unhandled exception lt  Description gt  lt AppDomain gt DBSync exe lt  AppDomain gt  lt Exception gt  lt ExceptionType gt MySql Data MySqlClient MySqlException  MySql Data  Version 6 7 4 0  Culture neutral  PublicKeyToken c5687fc88969c44d lt  ExceptionType gt  lt Message gt Unable to connect to any of the specified MySQL hosts  lt  Message gt  lt StackTrace gt  at  MySql Data MySqlClient NativeDriver Open   at MySql Data MySqlClient Driver Open   at MySql Data MySqlClient Driver Create MySqlConnectionStringBuilder settings  at MySql Data MySqlClient MySqlPool CreateNewPooledConnection   at MySql Data MySqlClient MySqlPool GetPooledConnection   at MySql Data MySqlClient MySqlPool TryToGetDriver   at MySql Data MySqlClient MySqlPool GetConnection   at MySql Data MySqlClient MySqlConnection Open   at DBSync MainForm BtnCalculateClick Object sender  EventArgs e  in c  Documents  and Settings Test01 My Documents SharpDevelop Projects DBSync DBSync MainForm cs line 51 at System Windows Forms Control OnClick EventArgs e  at System Windows Forms Button OnClick EventArgs e  at System Windows Forms Button OnMouseUp MouseEventArgs mevent  at System Windows Forms Control WmMouseUp Message amp amp amp  m  MouseButtons button  Int32 clicks  at System Windows Forms Control WndProc Message amp amp amp  m  at System Windows Forms ButtonBase WndProc Message amp amp amp  m  at System Windows Forms Button WndProc Message amp amp amp  m  at System Windows Forms Control ControlNativeWindow OnMessage Message amp amp amp  m  at System Windows Forms Control ControlNativeWindow WndProc Message amp amp amp  m  at System Windows Forms NativeWindow DebuggableCallback IntPtr hWnd  Int32 msg  IntPtr wparam  IntPtr lparam  at System Windows Forms UnsafeNativeMethods DispatchMessageW MSG amp amp amp  msg  at System Windows Forms Application ComponentManager System Windows Forms UnsafeNativeMethods IMsoComponentManager FPushMessageLoop IntPtr dwComponentID  Int32 reason  Int32 pvLoopData  at System Windows Forms Application ThreadContext RunMessageLoopInner Int32 reason  ApplicationContext context  at System Windows Forms Application ThreadContext RunMessageLoop Int32 reason  ApplicationContext context  at System Windows Forms Application Run Form mainForm  at DBSync Program Main String   args  in c  Documents and Settings Test01 My Documents SharpDevelop Projects DBSync DBSync Program cs line 27 lt  StackTrace gt  lt ExceptionString gt MySql Data MySqlClient MySqlException  0x80004005   Unable to connect to any of the specified MySQL hosts  at MySql Data MySqlClient NativeDriver Open   at MySql Data MySqlClient Driver Open   at MySql Data MySqlClient Driver Create MySqlConnectionStringBuilder settings  at MySql Data MySqlClient MySqlPool CreateNewPooledConnection   at MySql Data MySqlClient MySqlPool GetPooledConnection   at MySql Data MySqlClient MySqlPool TryToGetDriver   at MySql Data MySqlClient MySqlPool GetConnection   at MySql Data MySqlClient MySqlConnection Open   at DBSync MainForm BtnCalculateClick Object sender  EventArgs e  in c  Documents and Settings Test01 My Documents SharpDevelop Projects DBSync DBSync MainForm cs line 51 at System Windows Forms Control OnClick EventArgs e  at System Windows Forms Button OnClick EventArgs e  at System Windows Forms Button OnMouseUp MouseEventArgs mevent  at System Windows Forms Control WmMouseUp Message amp amp amp  m  MouseButtons button  Int32 clicks  at System Windows Forms Control WndProc Message amp amp amp  m  at System Windows Forms ButtonBase WndProc Message amp amp amp  m  at System Windows Forms Button WndProc Message amp amp amp  m  at System Windows Forms Control ControlNativeWindow OnMessage Message amp amp amp  m  at System Windows Forms Control ControlNativeWindow WndProc Message amp amp amp  m  at System Windows Forms NativeWindow DebuggableCallback IntPtr hWnd  Int32 msg  IntPtr wparam  IntPtr lparam  at System Windows Forms UnsafeNativeMethods DispatchMessageW MSG amp amp amp  msg  at System Windows Forms Application ComponentManager System Windows Forms UnsafeNativeMethods IMsoComponentManager FPushMessageLoop IntPtr dwComponentID  Int32 reason  Int32 pvLoopData  at System Windows Forms Application ThreadContext RunMessageLoopInner Int32 reason  ApplicationContext context  at System Windows Forms Application ThreadContext RunMessageLoop Int32 reason  ApplicationContext context  at System Windows Forms Application Run Form mainForm  at DBSync Program Main String   args  in c  Documents and Settings Test01 My Documents SharpDevelop Projects DBSync DBSync Program cs line 27 lt  ExceptionString gt  lt DataItems gt  lt Data gt  lt Key gt Server Error Code lt  Key gt  lt Value gt 1042 lt  Value gt  lt  Data gt  lt  DataItems gt  lt  Exception gt  lt  TraceRecord gt    I can connect to the mysql server through mysql workbench and query the database  It is only the code that doesn t work  Edit  I have noticed that the error crops up when I am using sharpdevelop and not when I am using Visual Studio

User · Answer

I am running mysql on a computer on a local network  MySQL Workbench could connect to that server  but not my c  code  I solved my issue by disconnecting from a vpn client that was running

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Sometimes spacing and Order of parameters in connection string matters  based on personal experience and a long night  S   So stick to the standard format here      Server myServerAddress  Port 1234  Database myDataBase    Uid myUsername  Pwd myPassword

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In my case the hosting had a whitelist for remote connection to MySql  Try to add your IP to whitelist in hosting admin panel

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Just ran into the same problem  Installing the  NET framework on the target machine solved the problem   Better yet  make sure all required dependencies are present in the machine where the code will be running

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Since this is the top result on Google   If your connection works initially  but you begin seeing this error after many successful connections  it may be this issue   In summary   if you open and close a connection  Windows reserves the TCP port for future use for some stupid reason   After doing this many times  it runs out of available ports   The article gives a registry hack to fix the issue        Here are my registry settings on XP 2003   HKEY LOCAL MACHINE SYSTEM CurrentControlSet Services Tcpip Parameters MaxUserPort 0xFFFF  DWORD  HKEY LOCAL MACHINE SYSTEM CurrentControlSet Services Tcpip Parameters MaxUserPort TcpTimedWaitDelay 60  DWORD        You need to create them  By default they don t exists       On Vista 2008 you can use netsh to change it to something like   netsh int ipv4 set dynamicport tcp start 10000 num 50000       but the real solution is to use connection pooling  so that  opening  a connection really reuses an existing connection   Most frameworks do this automatically  but in my case the application was handling connections manually for some reason

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I was having the exact same error   Here s what you need to do   If you are using MAMP  close your server  Then click on the preferences button when you open up MAMP again  before restarting your server of course    Then you will need to click on the ports tab  and click the button  Set Web and MySQL Ports to 80  amp  3306

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Sometime the problem could be on your windows firewall  make sure your server allow access to all port associated with your mysql database

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using System  using System Linq  using MySql Data MySqlClient   namespace ConsoleApplication1       class Program               static void Main string   args                            add here your connection details             String connectionString    Server localhost Database database Uid username Pwd password                try                               MySqlConnection connection   new MySqlConnection connectionString                   connection Open                     Console WriteLine  MySQL version      connection ServerVersion                   connection Close                              catch  Exception ex                                Console WriteLine ex                             Console ReadKey                        make sure your database server is running if its not running then its not able to make connection and bydefault mysql running on 3306 so don t need mention port if same in case of port number is different then we need to mention port

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use SqlConnectionStringBuilder to simplify the connection   System Data SqlClient SqlConnectionStringBuilder builder   new System Data SqlClient SqlConnectionStringBuilder    builder  Initial Catalog      Server   builder  Data Source      db   builder  integrated Security     true  string connexionString   builder ConnectionString  SqlConnection connexion   new SqlConnection connexionString   try   connexion Open    return true    catch   return false

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for users running VS2013  In windows 10    Check if apache service is running  since it gets replaced with World wide web service    run netstat -n to check this    stop the service  start apache  restart the service

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In my case by removing portion  port 3306   from the connection string solved the problem

User · Answer

Try this   MySqlConnectionStringBuilder conn string   new MySqlConnectionStringBuilder    conn string Server    127 0 0 1   conn string Port   3306  conn string UserID    root   conn string Password    myPassword   conn string Database    myDB      MySqlConnection MyCon   new MySqlConnection conn string ToString      try       MyCon Open        MessageBox Show  Open        MyCon Close        MessageBox Show  Close      catch  Exception ex        MessageBox Show ex Message

User · Answer

I found the solution to my problem  I was having the same issue  Previously I had my connection string as this notice the port  3306 needs to be either attached to the server like that 127 0 0 1 3306 or removed from server like that Server 127 0 0 1 Port 3306 depending on your  NET environment   quot Server 127 0 0 1 3306 Uid username Pwd password Database db  quot   It was running fine until something happened which I am not sure exactly what it is  might be a recent update to my  NET application packages  It looks like format and spacing of the connection string is important  Anyways  the following format seems to be working for me   quot Server 127 0 0 1 Port 3306 Uid username Pwd password Database db  quot   Try either of the versions and see which one works for you  Also I noticed that you are not using camel casing  this could be it  Make sure your property names are in capital casing like that Server Port Uid Pwd Database

User · Answer

If you are accessing the live database by using localhost URL then it will not work   Please deploy your service or website on IIS and create URL and then access the database by using new URL  It will work

User · Answer

Update your connection string as shown below  without port variable as well    MysqlConn ConnectionString    Server 127 0 0 1 Database patholabs Uid pankaj Pwd master     Hope this helps

[c#] Unable to connect to any of the specified mysql hosts. C# MySQL

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