Scenario:
An attempt to login to TDV with the Studio client returns this error:
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Failed to finish connect: 'Connection timed out: no further information'.[jdbc-1906503] 
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* During this time, you may notice that the browser-based Manager tool can still successfully login to the TDV server, confirming the TDV service.
* cs_studio.log may capture the following error stack trace
 

Caused by: java.io.IOException: Failed to finish connect: 'Connection timed out: no further information'.[jdbc-1906503]
        at cs.jdbc.driver.protocol.ChannelConnection.finishConnect(ChannelConnection.java:335)
        at cs.jdbc.driver.ReplySelectThread.run(ReplySelectThread.java:160)
Caused by: java.net.ConnectException: Connection timed out: no further information
        at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
        at sun.nio.ch.SocketChannelImpl.finishConnect(Unknown Source)
        at cs.jdbc.driver.protocol.ChannelConnection.finishConnect(ChannelConnection.java:332)
        ... 1 more

This reference to JDBC is key here. TDV Studio client will typically establish up to 3 concurrent sessions in TDV server. One of them can be a JDBC connection which is required for various specialized Studio UI functionality.  The JDBC session is ephemeral and only opened and maintained as long as needed by the Studio, while the Studio's http sessions are persistent.  

As a basic sanity check, verify the server's JDBC listener by running /apps/jdbc/JdbcSample.sh locally in a shell session on the server host. Any sample test query you choose to use in this tool should receive a response, as long as the JDBC port was not intentionally disabled in TDV. If the JdbcSample tool succeeds locally, then next test a telnet connection from a Windows desktop to the TDV host's port 9401 (or your specific base port +1).

Example of a TDV host's port blockage against a Windows client (seen in a Windows command session):
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C:\telnet <your TDV hostname> 9401
Connecting <your TDV hostname>...Could not open connection to the host, on port 9401: Connect failed
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How to resolve "Connection timed out" error while logging into TIBCO Data Virtualization (TDV) Studio ?

If there is a telnet error as above, resolve any port blockage between the Windows client and the TDV server host for port 9401 (or your specific base port +1).
As previously mentioned, TDV Studio needs to login to both the TDV server's base port (ie; 9400) and the JDBC port (base port +1).