Cannot create folder ".well-known" with winSCP

I cannot create folder ".well-known" with winSCP - it just vanishes and does not appear listed then comes back with Error "Directory with name '.well-known' already exists" if attempted again. This is essential for registering a PWA in the Google Play Store.

Do you have showing of hidden files turned on?
https://winscp.net/eng/docs/ui_file_panel#hidden_files

Thank you Martin - that worked