My 97 Ford f350 cranks but does not start I have dual tanks

The truck has been running perfectly fine no
missing no hesitation nothing. I I parked the
truck and went as to the store for about an
hour come back out and it did not start it
cranks but will not start. Keep in mind both
tanks works perfectly fine until this
happened. I don't have a meter to check the
voltage but I did pull the fuel line at the fuel
filter and turn the truck on nothing came out
I do not hear my pumps either the front or
the back working what could this be.