How to make friends with all browsers in Ubuntu?

Question

Browsers

The essence of the problem is this: two browsers (Firefox and Chromium) do not work at the same time? At first there was such a problem that Chrome did not play the video. After multiple reinstallations of the browser and the adobe plugin - nothing was successful))))))). The reboot also did not give the expected effect, but after the system updates, ubunta - "wow!" everything worked. But a new problem appeared - firefox does not work. Only firefox does not load at all. How to make both browsers friends?
PS Browsers are both needed for production needs.

Answer 1

What does "doesn't work" mean? Run in the terminal, output to the studio.
The Flash plugin may not work because it's an old holey piece of you-know-what, the latest versions of Firefox and Chrome block it because of the holes.