An error in ora-12170, mosora-12170 is reported when a remote machine is connected to a db on windows.

An error in ora-12170, mosora-12170 is reported when a remote machine is connected to a db on windows.
Error ora-12170 reported when connecting to db on windows from remote machine

Reference Original:
Windows: ORA-12170 Attempting to Connect from Remote Client (Doc ID 748461.1)

Applicable:
Oracle Net Services-Version 9.2.0.1 to 11.2.0.3 [Release 9.2 to 11.2]
Z * OBSOLETE: Microsoft Windows
Generic Windows
Microsoft Windows (32-bit)
Microsoft WindowsGeneric WindowsMicrosoft Windows (32-bit)

Symptoms:

Unable to connect to db via listener, client connection timed out with error: ORA-12170

There is no problem with the local connection on the db server.

Cause:
The login users in listener service are different from those in database service.
In this case, the listener cannot spawn out the proprietary server process.

Solution:
In the windows service, find the listener service, right-click the listener service, find properties-login, and change its login user to an OS user that is the same as the database service.