I have the same issue.
Just bought a 2015 825i and it ran fine for an hour or so... several starts for small rides.
This morning, it turned over... fired, and then died.
After, it just turns over... no fire.
Removed the fuel line from the filter. Turned key, fuel pumps great.
Removed the spark plugs; they are dry and but not sparking when removed and grounded.
Was told the fuse block off of the battery might be blown, it is fine... 12 volts on both sides (at the wires)
Checked the three fuses under the dash.
Battery is 12.5volts
Question: are there any other safety or interlocks that have to be present.. before it fires? Seems like something is keeping fuel flow and spark from happening.
Thanks for any help!