!
error Finder
Error Code ERR
Incorrect PIN entered three times.
? What Causes This
Three consecutive incorrect attempts on the lock function.
✓ How to Fix It
Wait for the display to turn off and then try again after 20 seconds. Use code '618' as backup if forgotten.
Source: page 17 of the official manual
From the manual
This error code appears in:
Finder IB1C91 Bliss Wifi Chrono Thermostat