Hello, sometimes my miners turn off randomly, using 5.6d but I was also encountering the same issue on 5.4c.
There is no indication of why, looking at the logs all of the GPUs are reporting a proper hash and then I see this message
2021.05.19:05:14:23.233: unkn Quitting...
Windows? Ubuntu? Check the corresponding times in your system logs and see what happened at that time.
then all of the GPUs reset and the program closes.
Any ideas?