Thmbs size not correct in frontend

Replies: 0

Hello,
I have set a gallery with thum sizes 240×240 in 3 rows, but what I see are thumbs that are actually about 210×210.
Am I missing somethings in the configuration maybe?

Thank you

screenshot: https://drive.google.com/open?id=1Og5n_AjnLKe7dijpRyO9RxDI3UskBp7r
configs: https://drive.google.com/open?id=1eX0z_55UNNWTQbjSaW_yixpjg51WRjhM

p.s.
both plugin and wordpress are latest version, just freshly installed