Solved by following this:
https://optimizory.atlassian.net/wiki/spaces/KB/pages/500269057/Facing+ngrok+error+6022+even+after+installing+the+auth+token
TL;DR:
For some reason npm got confused with which ngrok to use. To solve:
Copy the ngrok.yml to /Users/[name]/.ngrok2/ngrok.yml
Alternatively from project folder: ./node_modules/ngrok/bin/ngrok authtoken [your authhtoken]
Visit ngrok tunnel location and confirm dialog