Hello gab_o,
Thank you for using Apple Support Communities. Sounds like you're receiving an error code when trying to use iTunes. If so, we'd like to shares some helpful steps that could help resolve this issue. You had mentioned that iTunes isn't able to connect to the internet, possibly Apple services. We have a resource you can review that includes steps you can try for when facing similar issues. Click here: If you can't connect to the App Store, iTunes Store, or other Apple services - Apple Support
The resource does step to make sure that you install any new updates available for your PC. If you do have pending updates, it would be a good idea to install them. Other steps you can attempt can be found below:
1.) Temporality disable security softwares. This can sometimes interfere with communities between iTunes and Apple Services such as the iTunes Store.
2.) Restart iTunes and your PC, possibly even your home Wi-Fi network. This step does help refresh things
3.) Confirm your time zone and date settings are correct
4.) If your music library comes from different sources, make sure you save it by backing it up. You might need to reinstall iTunes.
If these steps don't help, you might want to reach out to Apple Support for help. You can reach them by using this link here: Get Support - Apple Support
Thank you for using Apple Support Communities.