RS485 4 in 1 Soil Probe

I'm trying to rig up the soil probe to be used in remote field research for manual data collection (not continuous) where a laptop is not practical. Therefore, I am trying to use an Android phone with modbus app. I'm currently using a rs485 usb adapter and usb to usb-c adapter to the phone and a 5V usb power bank. I have yellow and blue wires to pins 1 and 2 respectively, brown to red power source and black probe + black power to pin 5. The app runs but it appears there's no power to the probe. The TX light on the rs485 adapter blinks when I ask for a read but the RX does nothing. All the app configurations should be correct. Any suggestions?