Korean movie where a girl can see ghosts/fairies

I was watching a segment of a Korean movie, something like an ad, on Facebook.

As far as I remember, there is a school girl aged 8–10 years, maybe; she can see ghosts. She was in her school when she suddenly saw a ghost and the ghost tries to disturb her.

While the girl goes home, the school ghost (a female ghost) follows her and tells her to come back to school. The girl gets pissed off and she uses an umbrella (yellow in color; has some writing on it) to ward her off. That trick doesn't work, then a gentleman (wearing a black suit) comes into the picture and wards off the school ghost by hitting a black umbrella on the ground.

Then the girl and the gentleman have some conversation about bringing back something that belongs to him, in some place. The girl agrees to get it and she goes into a house lit up with lots of candles and a mirror.

There she retrieves whatever she needed, but while exiting, she ends up with another ghost/fairy (a lonely ghost) who tries to be cool with the girl. This lonely ghost learns that she was sent by another ghost that cannot enter his house. The lonely ghost is bound by 5 candles that have captured him (not like chained, just captured of some sort) and keep him inside that house. The lonely ghost promises (makes a contract) with the girl that if she blows out the candles, he will protect her from ghosts.

What was this movie?

Hwayugi (also known as A Korean Odyssey), a 2017–2018 Korean fantasy drama series

An unfortunate little girl with the power to see ghosts, Jin Sun Mi makes a deal with a conniving spirit (Son Oh Gong) to release him from a magical prison in exchange for his protection. She wisely makes him pledge a contract with her, but he wiggles out of his obligation as soon as he is free. Twenty-five years later, she’s still plagued by spirits, and when she coincidentally sees him passing in the street, she’s keen to collect on her contract.

Through the help of Woo Whee (another spirit keen to return to the heavenly world, played by Cha Seung Won), the use of a Geum Gang Go (essentially a magical handcuff), and Sun Mi’s quick thinking, Son Oh Gong’s got his work cut out for him if he is to remain free and continue his path of self-gain.

— Soompi, First Impressions: “Hwayugi” Brings Sharp Wit, Fantastic Performances, And Thrilling Fantasy