White screen on startup

One of my players reports that at startup of my SDL-based game, he’s only getting a white window in the middle of the screen and it hangs at that point. This issue does not occur on my system, so I’m having trouble reproducing this. Maybe somebody can give me a suggestion what could cause this? Thanks!

This is using the latest SDL2 libraries. I assume that this means SDL_CreateWindow does work, and the issue lies with the other functions.
window = SDL_CreateWindow(“name”, SDL_WINDOWPOS_CENTERED_DISPLAY(0), SDL_WINDOWPOS_CENTERED_DISPLAY(0), 1280, 720, 0);
renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);