Linux Realdash Video intro not working after sudden login&preset reset

Hello, im working on a Custom Racing Gauge with Raspberry pi 4B + diet pi + XFCE.
Month ago, i was pretty worked well with Realdash Application in offline. But all of sudden, yesterday i just got login message with cannot bypass it, and i tried reboot but almost half of settings are gone. Thanksfully it just got barely synchronized, but still Video intro(it is Mp4) not working.

I tried even purge removing realdash and re install it, but still mp4 files not working in video intro.
But jpeg works, i think there is something wrong with video play thingy. Is there any suggests for works video intro again? Should i install some additional video driver?

Hard to say what happened there. You are saying that mp4 video playback was working and then suddenly stopped working without intalling any updates etc?

First thing that comes to mind is that there is something wrong with your Linux filesystem, maybe a corrupted mp4 file or disk partition?