VGA is from the days when monitors could not auto configure. Basically, you either used some default mode, or you installed a “driver disk” which was a list of the monitor’s specs, and the driver would read those specs.
After this, using digital interfaces, a “DDC” wire was added. This allowed the video card to ask the monitor what its specs were, and this was the first plug-n-play for video.
On a desktop PC you can set modes manually (such as required by VGA), or let it auto configure if a more modern connector is present (such as HDMI, DVI-D, or DisplayPort). The embedded Jetson systems do not allow manual setting, and work only with auto configuration, so it seems the default resolution does not coincide with something the monitor supports.
Mostly I suggest switching to true HDMI. You could modify your kernel source and put in a new kernel which has a default fallback mode your monitor supports, but that’s a lot of work. If you want to go that route, then see this thread: