You'll get this message If the clock battery in the 436 is drained. The battery only charges when the radio is turned on, so if you've not used your radio for a while you will get this error. I think I've gotten this message after just a couple weeks of non-use. When your radio is new you have to let it run continuously for 50 hours to fully charge that battery. If you did that, and you've been using your radio daily ever since, then you likely have a bad RTC battery and need the repair program that Buddrousa linked to.
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