Are you sure that you let it finish? Some renderers work one “tile” at a time. (Used to be 8 tiles at a time.) There’s a progress indicator in the upper corner of the screen. (It’s not nearly as obvious as it ought to be …) Maybe it’s split the image into two tiles and you stopped it before it finished calculating the lower one.
Not entirely sure but could be that your CPU or GPU - whichever you used to render - ran out of memory. I feel like I’ve run into this myself once or twice although I can’t remember exactly why. Which rendering engine are you using?
I haven’t encountered this problem but I’d save the file and reboot. Select GPU (vs CPU) in render settings if you have a dedicated graphics card. Then I’d render using EEVEE (assuming your freeze up occurred when rendering in CYCLES). If EEVEE render goes ok, try it again in CYCLES and set frame rate to 128 or lower. If you’ve already tried all this, sorry I wasn’t of much help to you.