My environment : Debian 10
zephyr SDK 0.10.3
zephyr 2.1.0-rc2

I'm Interfacing Max44009 with nrf52840 on a custom make board in zephyr. I'm using the sample sensor program for MAX44009. Configured with appropriate overlay and prof.conf according to the MAX44009 datasheet . After flashing I'm getting Illegal use of ESPR on serial console.
 
I can't seem to figure why this is happening as i'm not majorly modifying with the sample code.
Please suggest debugging .
Thanks in advance.