Check the following to address this issue.
1.
Gas valve coils
Igniter glows, then shuts off without igniting gas - the problem is
probably with defective coils (black, located on top of the gas
valve). It is recommended to replace all coils (usually two or
three) if found defective.
Note: Sometimes the whole gas valve may be defective, thus not
letting the gas out. However, this problem is not common.
2.
Thermal fuse
Most dryers have a thermal fuse, which burns out when the dryer
overheats, in which case the dryer will either not run at all or
stop heating. The fuse is usually located on the vent duct, inside the
dryer. A blown fuse will show no continuity when measured with a
meter. Before replacing the fuse, make sure the blower wheel is not
broken or clogged, and there is nothing blocking the venting.
Note: It is recommended by most dryer manufacturers to replace a
hi-limit thermostat when replacing a thermal fuse.
3.
Igniter
Igniter may burn out or break. Replace the igniter if found
defective.
Note: Igniters are very fragile and break easily. It is recommended
to handle the igniter only touching the ceramic part of it (usually
white in color).
4.
Flame sensor (or radiant heat sensor)
Replace the sensor (located near the igniter) if found defective.