Cyber Panel cannot detect the distro version Ubuntu 21.04

I am trying to install it, but it cannot see the distro version.
I got this:
-rwxr-xr-x 1 root root 1934 Sep 6 16:39*
root@RexServer:~/panel# sh
Unable to detect your OS…

CyberPanel is supported on Ubuntu 18.04, Ubuntu 20.04, Ubuntu 20.10, Ubuntu 22.04, CentOS 7.x, CentOS 8.x, CloudLinux 7.x, CloudLinux 8.x and AlmaLinux 8.x…

My OS is Ubuntu 21.04, its VPS server.
Can someone gave a hand please ?

21.04 not supported use 20.04