Conversation so far:
What did Charlie Parker do in Charlie Parker's early career?
In the late 1930s Parker began to practice diligently.
During this period he mastered.
What did he master?
improvisation and developed some of the ideas that led to bebop.
Did he work with anyone else of note?
1938 Parker joined pianist Jay McShann's territory band.
What did they do together?
The band toured nightclubs and other venues of the southwest, as well as Chicago and New York City.
Did they gain any recognition then?
Parker made his professional recording debut with McShann's band.
Where else did they tour?
CANNOTANSWER.
Are there any other interesting aspects about this article?
In 1937, Parker played at a jam session at the Reno Club in Kansas City.
His attempt to improvise failed.

Question: Why did it fail?
Self-contained rewrite: Why did Parker's attempt to improvise fail?