No, overnight or swing trading is not allowed on Ylos Trading. Here are some explanations about this: 

Overnight Trading:

Prohibited: All positions must be closed at least 30 minutes before the end of the trading day.

Swing Trading:

Prohibited: Swing trading, which involves holding positions for several days, is also not allowed. The trading strategy on Ylos must be based on intraday operations, where positions are opened and closed within the same trading day.

What happens if I leave an order open after the market closes? 

Your account will be blocked and your balance will not be restored, as this would be an operation initiated on one trading day and closed only on the next, and only Day Trade operations - opened and closed on the same trading day - are allowed on Ylos.

My account failed because I remained positioned after the market closed, what happens to my balance? 

The balance will be reset to zero regardless of the accumulated value in the account, whether the account is a challenge or funded type.

What time should I close my trades to avoid losing my account by remaining positioned after the market closes?

At least 30 minutes before the market closes, up to 3:30 PM (Chicago time) from Monday to Friday on regular days, with the market operating on normal hours. 

On holidays and special dates, the closing time may be brought forward, and all trades must be closed 30 minutes before the market closes.