I changed from the Webmin Themes page but no change appears. I have restart but still no change. So I changed manually the theme directly in the 2 configuration files and restart webmin. It works. All is good now like before the update. Thank you for your help !
It works now after removed the line. Yes, it is the theme I used many years. I have rollback to use it and I can login now with this theme. But I don't understand why the appearances of the website is not the one I used until now. Like it's still the gray theme.
Here are my config files. miniserv.conf : port=10000 redirect_port=443 addtype_cgi=internal/cgi realm=Webmin Server logfile=/var/webmin/miniserv.log errorlog=/var/webmin/miniserv.error pidfile=/var/webmin/miniserv.pid logtime=168 ppath= ssl=1 no_ssl2=1 no_ssl3=1 env_WEBMIN_CONFIG=/etc/webmin env_WEBMIN_VAR=/var/webmin atboot=1 logout=/etc/webmin/logout-flag listen=10000 denyfile=\.pl$ log=1 blockhost_failures=5 blockhost_time=60 syslog=1 session=1 premodules=WebminCore userfile=/etc/webmin/miniserv.users...
I don't want to reinstall it, there would be a lot of work to reconfigure it. But I have downgraded it, then upgraded it again without error. The update was processed by the repository via apt. I will post the configuration files later. Thank you.
My OS is Debian 11. Yes I have rebooted my server and webmin but the bug was always here.
undefined get_miniserv_config after 2.010 update