Intermittant Starting Failure

Upon turning the key to my '08 2500 Dodge Sprinter with < 7k on it, I hear a solid click, (am I hearing the solenoid?), but no starter activity.
After five or more attempts, it may start and run normally. I cleaned the battery post & leads, and have 15V. Any ideas? Please advise. Thanks, Clay

During the no start condition voltage needs to be checked at critical location through the starter system to best determine where the fault is. Location checked, the battery, voltage drop the cables and ground, solenoid both the signal wire and battery lead.

A few things that have come before:

Poor connection in the battery cables both positive and neg (both chassis and engine ground)(voltage drop test)

Y battery cable corroded crimps cause high resistance (poor connection).

Starter solenoid contacts poor.

Starter relay failing ( no voltage to solenoid signal wire during cranking) poor connection internal relay contacts.

Or the starter itself is failing sticky bushes, internal connection etc

Hey, Showkey,
Thanks for the leads. I apologize for the delay in acknowledging you suggestions, but The Truck started before I read your reply, and thinking that the problem had self-resolved, (Magic?), I did not return to the Forum until now. Here it is a month later, and the problem has re-occurred. Without another set of hands, and little knowledge of electrics, would you recommend trying to jump the starter? I used to have reasonable luck doing that on my '58 VW Transporter using a screw-driver or pair of pliers. What do you think?
Thanks,
Clay