Control surface only works one way

Hi all, So far I've been able to get my TASCAM 1884 control surface to respond to changes in REAPER, but I've not been able to get the TASCAM to control settings within REAPER. For example, I can move a track fader with my mouse in REAPER and the motorized faders on the TASCAM respond accordingly, but if I physically move a fader on the TASCAM, the track faders won't move in REAPER. I'm using the Mackie Universal control surface mode both within REAPER and within the TASCAM device configuration... Any ideas how I can get the TASCAM to work both ways??

In midi devices, do you have it enabled and also have control enabled?

I've tried enabling it in the MIDI devices menu, but I always get an error "The following MIDI inputs could not be opened..." (See attached pic)

Came across a really nice post on youtube that explains how you can get any controller to control reaper faders etc. It takes time to assign the faders and actions but IT WORKS.

Make sure the 1884 is set on computer mode. Mine will work the faders, trasport controls and a few misc buttons. But all the buttons dont work right.