WHAT IS THE ISSUE?!

        [HttpPost]
        [Route("A3Bans/searchBan")]
        public string oSearchBan(tBan ban)
        {
            {
                tBan bans = new tBan();
                string dbConnection = "datasource=127.0.0.1;port=3306;username=admin;password=00000";
                MySqlConnection conDataBase = new MySqlConnection(dbConnection);
                MySqlDataReader dbReader;
                MySqlCommand SelectCommand = new MySqlCommand ("SELECT * FROM a3bans.bans WHERE GUID =" + dbReader.GetString(ban.GuidOrIP);
                conDataBase.Open();
                dbReader = SelectCommand.ExecuteReader();
                while (dbReader.Read())
                {
                    tBan searchBan = new tBan();
                    searchBan.GuidOrIP = dbReader.GetString("GUID");
                    searchBan.BanType = dbReader.GetString("BanType");
                    searchBan.BanReason = dbReader.GetString("Reason");
                    searchBan.Proof = dbReader.GetString("Proof");
                    bans = searchBan;
                }
                dbReader.Close();
                return bans.Proof;


            }
        }