How to install Jitsi-meet server in a VPN?

Hi All,
I’d like to install jitsi-meet on a machine that is connected to a VPN for internal use with my colleagues. I tan the install procedure as described in the quick install guide and used the server’s VPN IP address as a host. However, when I got to the ssl certificate I tried Let’s Encrypt, which doesn’t work with bare IP address.
I don’t have a DNS on the VPN. Can you suggest a workaround for this case?

Regards
Georgi

There is no solution for this. This is how Let’s Encrypt works, it needs a working DNS entry and resolves it and connects to that server in order to verify it so it can create a certificate.
You will need to use self-signed or buy certificates from some authority and install them on the server.