Try the other key to be sure. If it fails then it's an issue with the car which hopefully is under warranty still.
If it works then it's obviously the key and would be replaced if under warranty.
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*** SOLD *** 2013 BMW M5 | Space Grey | MSR Stage 3 Tune | Catless Downpipes | MSR Intake and Charge Pipes | MSR Exhaust (Prototype) | Vorsteiner Rear Diffuser | RW Carbon Front Lip | RW Carbon Trunk Spoiler| Vorsteiner VS-310 Forged Wheels | Escort 9500CI w/Laser Jammers
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