Try to add Cluster Webmin Servers

SYSTEM INFORMATION
OS type and version REQUIRED
Webmin version REQUIRED

stuadmin@lab1:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 24.04.3 LTS
Release: 24.04
Codename: noble

cat /usr/share/webmin/version
2.520

Adding lab2.test.example ..

HTTP error : HTTP/1.0 302 Moved Temporarily

http 302 is a redirect, not an error.
error is someplace else, but without full logs/error, can’t help.