What are different bounce categories?

There are multiple bounce types that you can see in the report of a sent email. 
All bounce messages are primarily categorized in either Soft Bounce or Hard Bounce. 
A soft bounce is a temporary error. Once you fix it, the email can be delivered after some time. A hard bounce is an error because of which the email can never be delivered.

To know more about Email Bounces and Error Codes, click here.