I dont think this is the problem since it could load the whole map and the error shown is a 404 one as if there was no conection. Also, downloaded the android apps for APM and they load the map instantly. I’ll try to install in other pc and see what happens.
Have you tried to zoom out? If you don’t have GPS input, MP centers on the equator in the middle of the ocean. Google doesn’t have detailed aerial imagery for that region, which might be the reason for the error you see.