Problem starting 2001 B3000 truck on 2001 Mazda B3000

Had a problem one time, just the other day. Went to start truck at lunch, wouldn't turn over. Lights come on in dash, radio would play, chimes chimed. Made no clicking noise, no trying to turn over, nothing. Went out after work and it started right up. Does this sound more like a relay problem or an ignition problem? truck has a new battery and a new starter. Purchased truck a year ago and had problems with starter then, so replaced. Then before winter came, replaced battery with an Optima.

1 answer 2 comments
Intermittent issues are hard to figure, leaning toward security issue. Really needs to be check when it is not working to verify, without guessing.
Security issue? Such as? I'm really looking to find which direction to look.
PATS immobilizer system. Could the theft light have been flashing or staying on while trying to start.