Getting error when trying to connect: "System.EntryPointNotFoundException Unable to find an entry point named 'SQLFreeConnAttribsADONET' in DLL 'db2app64.dll'" (4333457)

Getting the error below when trying to connect to the database: 

System.EntryPointNotFoundException Unable to find an entry point named  'SQLFreeConnAttribsADONET' in DLL 'db2app64.dll'

Stack Trace:
在 IBM.Data.DB2.UnsafeNativeMethods.DB232.SQLFreeConnAttribsADONET(DB2SQLGetConnAttribsADONETParams& pParam)
在 IBM.Data.DB2.ConnSettingsFromXmlConfig.Dispose(Boolean disposing)
在 IBM.Data.DB2.ConnSettingsFromXmlConfig.Dispose()
在 IBM.Data.DB2.DB2ConnPool.ReplaceConnectionStringParms(DB2Connection connection, String szValue, DB2ConnSettings& pSettings, DB2ConnSettingsInternal& pSettingsInternal, Boolean bAttach, Boolean pushDownStrAppended)
在 IBM.Data.DB2.DB2Connection.set_ConnectionString(String value)
在 IBM.Data.DB2.DB2Connection..ctor(String connectionString)
在 Quest.Toad.DB2.DB2ToadConnection.CreateConnection()
在 Quest.Toad.Db.Connection.AllocConnection()
在 Quest.Toad.Db.Connection.Connect(Boolean notify)
在 Quest.Toad.Db.Provider.BackgroundConnector.CreateBackgroundConnection()