What are you trying to record? What do you have plugged into what on the Tascam?
Have a read through this …
If you are still having problems, post back with some more details.
Your problems most likely have to do with VST Connections, your track’s input/output routing and monitor enabled status, a setting on your Tascam (input/computer knob should be all the way to the computer side), or a combination of all these and maybe even something else thrown in for fun. Who knows? Not sure what you have tried so far.
Can you post screenshots of your VST Connections in/outs and of the main project window with your track’s inspector showing it’s in/outs?