This is the 11417th most frequent Russian word.
дневные
"Дневные" means "daytime" or "daily" in English.
In this sentence, 'дневные' is an adjective modifying 'занятия', meaning 'daytime' or 'occurring during the day.'
Дневные занятия начались в девять утра.
Daytime classes started at nine in the morning.
Here, 'дневные' describes 'встречи,' indicating that the meetings occur during the day as opposed to other times.
На дневные встречи приходят новые участники.
New participants come to daytime meetings.
In this context, 'дневные' modifies 'проблемы', meaning the issues happening during the day.