Have you tried logging out of the Spotify app on your Roku then enabling it again?
Click Account on the menu down the left side, the click the FORGET ME ON THIS DEVICE button.
Now click LOG IN on the next screen, and follow the instructions to go to your Roku.
Roku Community Streaming Expert I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well. If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X