You can't test electronic ballasts with DMM. If they're programmed start ballast, it gets more complicated.
There are two pins on each end and with programmed start, if the connection is poor, the ballast will lock out. The lamp and ballast can be fine but not work due to loose connection.
If you try to measure the voltage across instant start ballast with a meter, you may fry your meter. DMMs are not designed to take >600V @ 50,000Hz.
Dielectric grease like the kind used on spark plug boots help with prevention of socket corrosion somewhat.