An empty search
Reset the format, genre, and year filters, then try a shorter title. Search matches title text and original title text. It does not search actors or individual episode subtitles, so those queries may need the name of the film or show instead.
A saved-list problem
Check that you are using the same browser profile. Private windows and cleared website data do not preserve the same list. If the browser refuses storage, a save message explains that the change could not be kept.
A viewing problem
Watch now opens JustWatch, not a player inside SmashyStream. Check the selected country if a result seems wrong. For buffering or audio trouble after choosing a service, use that service’s player controls and help.