Part 107 UAS pilot reported climbing UAS into controlled airspace without LAANC authorization. Pilot stated they misinterpreted the authorization process.

Narrative

On Date at approximately XA:20 EDT; I was asked to photograph a large parcel of land for a realtor in my work as a real estate photographer. I operated my drone professionally and in good faith with local airport authorities; as I always do; but I may have broken an FAA protocol without realizing it at the time.I was flying in an extremely remote area out in the country; but still in Class E Airspace near a small airport (ZZZ). During my pre-flight check; I clicked on the Aloft app for height restrictions; and I saw that the area where I needed to fly had an auto approval of a maximum height of 200 ft. 'LAANC auto approval up to 200 ft. Further coordination available up to 400 ft.'The Aloft app took me through several steps to obtain this auto approval; and I was texted an authorization code which I then entered in the designated space on the app. I was then asked to confirm three statements about flying in a safe manner; being responsible; etc.; all of which I confirmed.Completely unaware; I mistakenly thought this auto approval process was to be able to fly up to 400 ft.; so I did. Halfway home I was suddenly struck with the realization that this auto approval process was very likely just to be able to fly up to 200 ft. I flew at 400 ft. When I returned home; I delved deeper into the Aloft app and discovered that I missed an additional small 'Get Authorization' button which would have taken me through the proper channels to get authorization to fly at 400 feet. It was at that moment my heart sank and I feared I broke FAA protocol. During pre-flight preparations; I was focused on the language 'auto approval' and assumed that meant I could fly beyond the 200-foot limit.This was a one-time occurrence due to ignorance on my part; and I assure you it will never happen again now that I understand the difference between 'auto approval' to fly up to the designated height and 'Get Authorization' to apply for permission to fly beyond the designated height limit.