Ubuntu 20.04

the image used for installing Ubuntu 20.04 has repositories set to yandex.ru adresses, but they dont work. I tried installing a GUI to get easy access to fixing the problem, but none of the required files can be downloaded. The Ubuntu 18.04 image uses the us-mirror and doesnt have this issue. Would be nice if this could be corrected. cause right now getting 20.04 is only possible by updating and upgrading all on 18.04 and only after installing installing the GUI.