I'd like to report a bug while making a search with lower case in a Turkish letter, though, it founds songs only if an upper case is used.
iPhone 7 Plus
Hey @anilberkc, welcome to the Community.Hope you're doing great!
What version of the Spotify app are you?
Try updating if you don't have the latest version, then try to do some basic troubleshooting, including:
I'd also suggest updating to iOS 13.2.2
Keep me posted.