Hello,
I installed Coturn and received a confirmation email. I noticed that it is suggested in this mail to test the configuration on Trickle ICE. There is the word turn: missing in the mail, maybe you could add it in the mail so that the test also works
TURN URI : turn:<YOUR_PUBLIC_IP_ADDRESS>:5349
TURN username: <YOUR_USERNAME>
TURN password: <YOUR_PASSWORD>
greetings from Sweden