5.9 diesel not starting after fuel/oil filter changed

Changed the oil and filter, also fuel
filter. I’ve done this several times no
problem.

This time truck will crank (plenty of
juice in battery) but the red in lower
right flashes.

Removed and put new fuel filter in.
Also used yellow fuel purge valve and
drained until filter chamber empty.

Turned key 2-3 seconds, didn’t start.
Turned key to run -not off position.
Could hear injector running. Repeated
3-4 times. Plenty of battery juice
cranking but not starting. Seems like
it’s not getting fuel, possible air in
system or air lock.

Battery loosing juice. Connected
charger to try again tomorrow. Never a
lick of trouble until today. 94k miles on
my 2004, 2500 4x4 w/ 5.9 Cummings
diesel.

Thoughts, suggestions please.