M-files photos taken by Nikon D7200 are all black.

I think your sensitivity and aperture are too small. If the sensitivity is not automatic, look at the parameters of your camera when using P file, and then apply this parameter to M file. If the film is the same as the P file, it means that your manual settings are incorrect, otherwise there is something wrong with the machine (but this is unlikely).

Judging from the current settings, the sensitivity is already very small and the aperture is also very small. Even when shooting during the day, if the light is not particularly strong or the clarity of the picture is required, the aperture you use is relatively small. If you must use this setting, try tripod +2 minutes long exposure.