Conversation so far:
What is napoli?
Maradona arrived in Naples and was presented to the world media as a Napoli player on 5 July 1984.
Are there any other interesting aspects about this article?
Napoli would win their second league title in 1989-90, and finish runners up in the league twice, in 1987-88 and 1988-89.
was there any other wins?
Other honors during the Maradona era at Napoli included the Coppa Italia in 1987.
Can you tell me more about this season?
At Napoli, Maradona reached the peak of his professional career.
What happened at the peak of his career?
Napoli would win their second league title in 1989-90, and finish runners up in the league twice, in 1987-88 and 1988-89.
How was him as a coach?
CANNOTANSWER.

Question: Why did his problem increase?
Self-contained rewrite: Why did Maradona problem increase?