Webmin over haproxy

I am new to haproxy I have manage to make it work some web pages over haproxy, but I can’t make it with webmin which is on port 10000. Can someone help me to push webmin over haproxy?
I get this error in browser when I try to access it
SEC_ERROR_INADEQUATE_KEY_USAGE
Just can’t make it to work with letsencrypt certificate from acme