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First, if you feel like it, remove the batteries from the rangefinder, and leave it that way for overnight, to rest-reset it.
Then put the batteries back in again (and note: if they are rechargeables, be sure they are recharged for some time, at least 3 hours, before trying them again... if they are non-rechargeables, be sure to try other, fresh, batteries at least briefly, in this device.)
If that then reveals the problem to be permanent or persistent, you can send your rangefinder for repair to Nikon USA, by way of:
If this is the information you needed, and answers your question completely, please rate my Answer. Thanks, ***** ***** luck.