My van will not crank when I turn the ignition key.The engine will not turn over on 1999 Chevrolet Express 2500

If I jump the starter solenoid with the ignition key in the on position it start up. After itnruns for a while it will crank with the ignition key, but if I let it set for a while I have to jump the starter solenoid again

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2 answers
have anti theft codes scanned to see if you have any faults with alarm to start with. you may have a key and or skim issue if this van have that system
possible ignition switch