i lost some time for this error. Its all about tokens.
run miio discover as root.
tokens are not share between user and root
you need to add them seperatly for root and your ubuntu/pi user

Hi

A little enhancement

Below script will also synchronize status between domoticz and Xiaomi air purifier

Requirments:
- script need 5 parameters as described.
Example entry in crontab ( runs every 15 minutes)

*/15 * * * * sh /home/pi/domoticz/scripts/xiaomi_air_purifier.sh 192.168.1.181 192 ...