when i click on Add product, i get the above error in the pic. Can anyone please help me on this how to solve?
This is an issue of the custom module, maybe you are missing luzern/conotification module. Check this module is enabled or not by this:
php bin/magento module:status Luzern_Conotification
I hope this will help you what your issue is
Please, try :
php bin/magento setup:upgrade php bin/magento cache:flush php bin/magento cache:clean
Then, don't forget to give rights on folders if needed.
Hope it helps.