This is probably a missconfiguration in NGINX or something wrong in the .env file.
Can you please share the content of /opt/openvidu/.env
Also could you share your nginx logs?: You can get them just with this commands:
sudo su
cd /opt/openvidu
docker-compose logs nginx
@icap84 I’m answering you here: OpenViduPro : Waiting for kibana - #2 by cruizba