"Page isn't redirecting properly" when I set gerrit.canonicalWebUrl

After installing Gerrit following Using Gerrit in production section from https://github.com/GerritCodeReview/docker-gerrit, the field was set automatically to this value:

[gerrit]
        canonicalWebUrl = http://eac32ee72f2b/

I want to use Gerrit behind a reverse proxy, so I configured Apache2 like this:

ProxyPass / http://192.168.19.241:8080/ nocanon

This works, but as soon as I set gerrit.canonicalWebUrl to https://gerrit.example.com, I get The page isn’t redirecting properly and the URL in the browser becomes https://gerrit.example.com//login/.

If I try to set the cannonical web url to https://gerrit.example.com/g/ and update Apache2 accordingly to:

ProxyPass /g/ http://192.168.19.241:8080/g/ nocanon

I get "Not found" message in the browser and the URL in the bar now reads https://gerrit.example.com/g//g//g//g//g//g//g//g//g//g//g//g//g//g//g//g//g//g//g//g//g. If I inspect the HTTP headers, for the initial request for page https://gerrit.example.com/g I get a 301 redirect to https://gerrit.example.com/g//g.

In all cases, the configuration httpd.listenUrl was proxy-http://*:8080.

Can anyone tell me what am I doing wrong? I would like to set the proper web URL, because it is visible in the links to checkout repositories over HTTP, and maybe also in other places.