How to calibrate monitor color in ubuntu?

Question

Monitors

There is a program designed to calibrate the colors of the displaycal.net monitor I'm trying to make some changes in the program and then apply, but the problem is that the button (Calibrate & profile) cannot be pressed, it seems to be inactive, I don’t know with what could this be related? PS: there are two identical monitors, but for some reason the colors on one of them are clearly warm, although the settings in the monitor itself are completely identical. One monitor is connected via HDMI, the other via Display Port.
UPD: I will be glad to consider other monitor calibration options for ubuntu.