I think the key for me, to get ecobee to re-send a PIN was to delete the java prefs:
from that link:
Another thing to try, but I doubt it will help at this early stage, is to stop the openHAB server, delete the Java Preferences file where any bad tokens could be stored (on Linux, this should work: rm -rf ~/.java/.userPrefs), and restart the openHAB server.
After I restarted openhab, another PIN was sent to the logs by the ecobee binding. (using a correct API key, etc)
Not sure if this will help with your echo connection as well.
Good luck!