Solved: Magento 2 admin url gives error
When you spend your time, money and effort on an e-commerce software, you want it to generate business for you. Is Magento 2 giving you trouble? Are you unable to open the admin panel? Does the error read Class Magento\Authorization\Model\RoleFactory does not exist? Do not fret. The issue is more common than you think. Learn how to solve the problem and get rid of the error.
Solved: Magento 2 admin url gives error - Class Magento\Authorization\Model\RoleFactory does not exist
This is most likely issue of var/generation directory, so apply below fixes, this may solve your admin login issue...
1) Clear var/generation directory
2) Check ownership and permission of var/generation directory