página en blanco

Hello, this is an English forum, so please post in English, as we do not have a Spanish-speaking forum.

Translating what you posted:
When I install Proxmox Datacenter, I enter the address with the port in the browser, but the page remains blank.

I have version 95.0.1 of Firefox installed.

This version of Firefox is ancient and not supported. Please update your Firefox to a current supported release. Latest Firefox release is 148.0 and the current ESR (long term support) version at time of writing this is 140.x