clearing the cache and installing the payment module

[cpujjwal]

This problem comes from the Mage module. You should disable this module from your project
php bin/magento module:disable Mage_Customer
Or alternatively, you can put debug in the file /app/code/core/Mage/Customer/Model/Observer.php so you can find out the reason for the error in this file

 

[zyhivan]

Thanks for sharing it, Thank you so much! Thank you so much!