Unable to use custom board with nRF Connect's Direct Test Mode application for nrf52833

[Noah]

Hello!

I am able to use the Direct Test Mode application on the nRF52833 development board using the pca10100 DTM firmware found in the 17.0.2 SDK over USB. However, when using the same firmware with a custom PCB also using the nRF52833 via J-Link, I am met with the following error in nRF Connect:

"Can not communicate with device. Make sure it is not in use by another application and that it has a Direct Test Mode compatible firmware."

Are there any firmware changes (such as pin mappings) that I'm supposed to change to allow this application to work with a custom PCB rather than a development board? Additionally, am I able to use any GPIO pins for Rx and Tx? 

Else, are there any other suggestions for solving this error?

Thank you in advance!

[Noah]

Do I need to change any GPIO's other than Rx and Tx for this?

[JONATHAN LL]

No, no other GPIO's is needed. Only change the RX and TX to the correct pins on the board you are testing. 

Regards,
Jonathan