Connection timeout from ASP.NET but OK from a console app

[maxima120]

I have ASP.NET running under IIS7 in 32 bit mode. I installed Oracle Instant Client 32 bit.

I can:
- connect and run tools like SqlPlus using TNS
- connect and run .NET code with Devart data provider from a console application using TNS
- connect and run .NET code with Devart data provider from the ASP.NET application using direct mode

I cannot
- connect and run .NET code with Devart data provider from the ASP.NET application using TNS

I got exception which doesn't make any sense (I can connect console test app using exactly same connection string):

Devart.Data.Oracle.OracleException (0x80004005): Server did not respond within the specified timeout interval
at Devart.Data.Oracle.a1.a(cg A_0, o A_1)
at Devart.Data.Oracle.OracleInternalConnection..ctor(cg connectionOptions, OracleInternalConnection proxyConnection)
at Devart.Data.Oracle.ay.a(r A_0, Object A_1, DbConnectionBase A_2)
at Devart.Common.DbConnectionFactory.a(DbConnectionPool A_0, r A_1, DbConnectionBase A_2)
at Devart.Common.DbConnectionPool.a(DbConnectionBase A_0)
at Devart.Common.DbConnectionPool.GetObject(DbConnectionBase owningConnection)
at Devart.Common.DbConnectionFactory.b(DbConnectionBase A_0)
at Devart.Common.DbConnectionClosed.Open(DbConnectionBase outerConnection)
at Devart.Common.DbConnectionBase.Open()
at Devart.Data.Oracle.OracleConnection.Open()
...

I don't see anything in the machine event logs or the IIS logs.. Any ideas how can I investigate it?

[Shalex]

I cannot
- connect and run .NET code with Devart data provider from the ASP.NET application using TNS

Devart.Data.Oracle.OracleException (0x80004005): Server did not respond within the specified timeout interval

1. Is this error permanent or intermittent?
2. Is "Oracle Instant Client 32 bit" the only Oracle Client on your workstation?
3. Specify your connection string (roughly, without credentials).
4. Tell us the full name, version of your Oracle Instant Client and the exact steps you have followed when installing/registering it on your system.
5. Is your workstation 32 bit or 64 bit?
6. Send us a screenshot of the Advanced Settings window of the application pool used by your web site in IIS.
7. What is the value of the "Platform target" property of your project in Visual Studio?
8. Does your code just open connection or try to fetch some data? (there is an obfucated line in stack trace before exception)
9. Try these connection string options: Pooling=true/false; Validate Connection=true/false; Does this make any difference?