Hi Karim_HT
Thanks for posting to the Apple Support Communities.
I understand the iTunes Store is not allowing you to download a playlist. You are getting an unknown error (-45061). I want to help! Is iTunes updated to the most recent version? If not, I would recommend updating iTunes. Here’s how to Update iTunes on PC - Apple Support
You can also try these suggestions:
Check the connection. This article talks the steps If you can't connect to the App Store, iTunes Store, or other Apple services - Apple Support
If possible, try using a different network to test.
If you use any third-party security software, try these tips and settings: Resolve issues between iTunes for Windows and third-party Security software - Apple Support
If you're still having issues, reach out to Apple Support: Contact Apple Support
Best Wishes.