Unable to detect that is running inside Docker in Ubuntu 20.04 LTS

It finds the error Unable to decode DMI.

root@c33b14d510ad:~/ctop/src/ctop# cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.3 LTS"