I see. I had not installed the access manager software, since it's not necessary to use the MiFi. I also didn't guess that it might help, since neither of the user's guides provided by Verizon indicate that the access manager does that. Also Verizon didn't bother to tell me when I tried to set up access, and this fact doesn't in any of the online help I can find.
But it does, so thanks for letting me in on Verizon's secret.