Not able to upload code to Adafruit Pro Trinket 5v

I am working on a project that involves using a pro trinket and an Uno. Multiple sensors are connected to the trinket and the trinket is connected to the Uno via TX, RX, and ground. Yesterday, I worked with this set up and received no errors but now I can't upload anything to the trinket. I am connected to the trinket via a FTDI cable.

What happens when you disconnect the RX / TX currently going to the Arduino Uno ?