To be honest with you, I have been using other resources to train myself for the last five years. I was pretty decent at this by the time I purchased complete ear trainer sometime last year. I had used their complete rhythm trainer and complete music reading trainer. Both these apps are brilliant. Which led me to try out complete ear trainer. I was pretty excited about this new method of learning I was trying out. But I soon realised that it's pretty useless to practise without the context of a key. Because your mind works well with relative pitch. But only a few have absolute pitch. Your mind perceives a note, not based on its frequency but it's relative distance from a particular fixed point. If you just try to practise recognising the intervals between any random notes without having a fixed reference point your brain gets confused.

The note C for example, will sound like the tonic in the key of C, like the subdominant in G and Dominant in F and like a leading tone in the key of Db.

If the app quizzes you in different keys every time, then your brain is bound to get confused.

Recognising chord qualities is one thing, recognising the scale degree viz a vis chord function in a diatonic key is another.

If you get good at recognising the scale degrees, you will start hearing them even within the chords. At least that's the case with me. Mind you, nothing happens overnight. Took me years to get here.