The underlying provider failed on Open error in with a C# app using oracle

I have a C# app that is written with Entity Framework utilizing two DB entities (Oracle)... However, I'm getting the following error on my test server...

Help would be appreciated...

Error:

The underlying provider failed on Open. and Details: Oracle.ManagedDataAccess.Client.OracleException (0x80004005): ORA-12154: TNS:could not resolve the connect identifier specified ---> OracleInternal.Network.NetworkException (0x00002F7A): ORA-12154: TNS:could not resolve the connect identifier specified at OracleInternal.Network.AddressResolution..ctor(String TNSAlias, SqlNetOraConfig SNOConfig, Hashtable ObTnsHT, String instanceName, ConnectionOption CO) at OracleInternal.Network.OracleCommunication.Resolve(String tnsAlias, ConnectionOption& CO) at OracleInternal.ConnectionPool.PoolManager3.ResolveTnsAlias(ConnectionString cs, Object OC) at OracleInternal.ServiceObjects.OracleConnectionImpl.Connect(ConnectionString cs, Boolean bOpenEndUserSession, OracleConnection connRefForCriteria, String instanceName) at OracleInternal.ConnectionPool.PoolManager3.Get(ConnectionString csWithDiffOrNewPwd, Boolean bGetForApp, OracleConnection connRefForCriteria, String affinityInstanceName, Boolean bForceMatch) at OracleInternal.ConnectionPool.OraclePoolManager.Get(ConnectionString csWithNewPassword, Boolean bGetForApp, OracleConnection connRefForCriteria, String affinityInstanceName, Boolean bForceMatch) at OracleInternal.ConnectionPool.OracleConnectionDispenser`3.Get(ConnectionString cs, PM conPM, ConnectionString pmCS, SecureString securedPassword, SecureString securedProxyPassword, OracleConnection connRefForCriteria) at Oracle.ManagedDataAccess.Client.OracleConnection.Open() at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)