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Usually happens when there's a problem with the baseband/ modem. You could try flashing the stock firmware for your device.
I haven't fooled around with Lenovo so not sure how.
What is your complete model number and I'll see what I can find.
Flashing the stock firmware should get the build and baseband to match and straighten everything out.
I have had it happen to a few older Samsung devices and recently to a Motorola when trying to flash a custom rom or trying to return to stock.