I had a similar issue. It was resolved by installing M4 and then Coturn using the guides in https://cwiki.apache.org/confluence/display/OPENMEETINGS/Tutorials+for+installing+OpenMeetings+and+Tools and it worked well.
``` * Note: If you follow the guide "Installation SSL certificates and Coturn for OpenMeetings 5.0.0-M4 on Ubuntu 18.04.pdf" and are you running your OM server at home/small-business using DynDNS, then one step will fail which is generating the Let'sEncrypt Certs. After 8 hours of searching in the internet, trying different DynDNS providers and different workarounds, the issue is resolved by tweaking the command mentioned in the guide as follow: sudo -H ./letsencrypt-auto certonly --standalone -d exemple.com -d www.exemple.com # change the command to below sudo -H ./letsencrypt-auto certonly --manual -d exemple.com -d www.exemple.com # this will require one more step, but it succeeds ``` Regards, Ahmad | Unix Home Academy https://www.facebook.com/unix.home/
