Insolence always has a negative connotation implying disrespect that is often provocative. His insolence towards the manager resulted in immediate dismissal.
Pro Tip 2/3
Informal Situations
Insolence might be more tolerated among friends as banter, but it's still risky. They laughed off his insolence as a quirky trait.
Pro Tip 3/3
Not Playful
Unlike 'cheeky', insolence is not seen as playful or endearing. What you see as fun, I see as insolence.