Ith-20r blinking inside temperature?

I have a Ith-20r and the inside temperature reading is blinking, and its way off.
Why is it doing this and how can I solve this?
Outside temperature is fine.

Please replace the batteries for the ITH-20R-I transmitter with new ones. If the battery power is low, its display will flash.

The battery indicator didn’t show empty so I never tried that.
I’m going to try. Thanks!