stop this warning for this specific message in logging

Dear all Experts,
Hope you will be fine I want to stop this warning for this specific message in logging.
Please let me know How I can stop by using login and prefix.

Am stoping this in the correct way??
Thanks
macc address.PNG
warr.PNG

From the documentation (https://help.mikrotik.com/docs/display/ROS/Log):

prefix (string; Default: ) prefix added at the beginning of log messages

As far as I know you can’t filter on the Message itself.

Update: I see you already are working on solving the cause:
http://forum.mikrotik.com/t/dhcp-untrusted-error/168871/1

yes Sir.
But unable to resolve this issue.
Is there any recommendation from you to communicate PC2 with Site A?
Thanks

My advice: use VLAN’s and use correct firewall settings.