You need to set a specific port for your clearml server and then just set a rule in your reverse proxy (eg. nginx) to make point the specific route you want toward that port

That might be an issue with clearml itself that fails to send proper resources if you change the path, that kind of path modification can be a hussle, if you have a domain name available I would suggest making a subdomain of it point to the ip of your clearml machine and just add site-enabled on nginx to point on it rather than doing a proxy pass

I tried via nginx but it doesn't work. This is the location configuration:
location /clearml/ {
proxy_pass None ;
}
in this way via the web the portal seems to load but then nothing is displayed.
If instead I change the location to just "/", then it works. Am I doing something wrong?

I will try as you indicated. Thank you