C# Error, Executing Stored Procedure, Stored Procedure is not available

I have a problem, I have stored procedure in my MySQL database called: sp_insertSupplier. This method is working when executed in mysql database.

I make this syntax in Save button

private void btn_supplier_save_Click(object sender, EventArgs e)
{
    string connections = Connection.mysqlconnectionbuilder();
    using (MySqlConnection conn = new MySqlConnection(connections))
    {
        using (MySqlCommand cmd = new MySqlCommand()) 
        {
            //make connection
            cmd.Connection = conn;
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.CommandText = "call sp_insertSupplier(@KD,@NM,@AL,@EM,@TLP);";
            cmd.Parameters.AddWithValue("@KD", createCode()); 
            cmd.Parameters.AddWithValue("@NM", txtsuppliernama.Text); 
            cmd.Parameters.AddWithValue("@AL", txtsupplieralamat.Text); 
            cmd.Parameters.AddWithValue("@EM", txtsupplieremail.Text); 
            cmd.Parameters.AddWithValue("@TLP",txtsuppliernotelp.Text);
            try
            {
                conn.Open();
                int result = cmd.ExecuteNonQuery();
                //check the result status
                if (result.Equals(1))
                {
                    DialogResult results = MessageBox.Show("Data berhasil ditambahkan! \n Apakah anda ingin input data lainnya? ", "Sukses!", MessageBoxButtons.OKCancel);
                    //cek apabila ingin menambahkan data lagi.
                    if (results.Equals(DialogResult.OK))
                    {
                        reset();
                    }
                    else if (results.Equals(DialogResult.Cancel))
                    {
                        this.Close();
                    }
                }
            } //end TRY
            catch (Exception exe)
                {
                    MessageBox.Show("Terjadi Kesalahan", "Perhatian!", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    StreamWriter _writer = new StreamWriter("E899911823.log");
                    _writer.WriteLine(exe.ToString());
                    Console.WriteLine(exe.ToString());
                } //END CATCH
            finally 
                {
                    conn.Clone();
                } //END FINALLY
        }
    }
}

but, when I execute the syntax, it shows an error:

MySql.Data.MySqlClient.MySqlException (0x80004005): Procedure or function '`call sp_insertSupplier(@KD,@NM,@AL,@EM,@TLP)`' cannot be found in database XXXXX

I don't think any problems with connection manager or the random method to create @KD.

I have still same problems, the console shows:

MySql.Data.MySqlClient.MySqlException (0x80004005): Procedure or function '`call sp_insertSupplier`' cannot be found in database '`XXXXX`'.
at MySql.Data.MySqlClient.ProcedureCache.GetProcData(MySqlConnection connection, String spName)
at MySql.Data.MySqlClient.ProcedureCache.AddNew(MySqlConnection connection, String spName)
at MySql.Data.MySqlClient.ProcedureCache.GetProcedure(MySqlConnection conn, String spName, String cacheKey)
at MySql.Data.MySqlClient.StoredProcedure.GetParameters(String procName, DataTable& proceduresTable, DataTable& parametersTable)
at MySql.Data.MySqlClient.StoredProcedure.CheckParameters(String spName)
at MySql.Data.MySqlClient.StoredProcedure.Resolve(Boolean preparing)
at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
at SerbaManisInventory.SupplierAdd.btn_supplier_save_Click(Object sender, EventArgs e)

I just rewrite the code so that the code like this:

using (MySqlCommand cmd = new MySqlCommand()) 
{
    cmd.Connection = conn;
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.CommandText = "call sp_insertSupplier";
    cmd.Parameters.AddWithValue("@KD", createCode()); 
    cmd.Parameters.AddWithValue("@NM", txtsuppliernama.Text);
    cmd.Parameters.AddWithValue("@AL", txtsupplieralamat.Text); 
    cmd.Parameters.AddWithValue("@EM", txtsupplieremail.Text);
    cmd.Parameters.AddWithValue("@TLP",txtsuppliernotelp.Text); 
    try
        {
            ...