How can I correct the error in the query? [URI 2992 Higher Average Wage Divisions]

Question

25% URI error. Why is the query not ordering? My query:

select distinct on (de.nome)
    de.nome as name_dep, 
    di.nome as name_div, 
    coalesce(round(avg(ve.valor), 2) , 0) as avg_salary
from departamento de
inner join divisao di    on di.cod_dep = de.cod_dep
inner join empregado em  on em.lotacao_div = di.cod_divisao
inner join emp_venc ev   on ev.matr = em.matr
inner join vencimento ve on ve.cod_venc = ev.cod_venc
group by de.nome, di.nome
order by de.nome, avg(ve.valor) desc

SQL: https://pastebin.com/7PyF9bDT

URI: https://www.urionlinejudge.com.br/judge/en/problems/view/2992