Are you using Deezer under cooperate network ? 

Hello @Isabelle Stolar,
As @Noam Asulin mentioned, the issue can be cause by several reasons, but most common ones are:

• Ad Blockers: If you have ad/tracker blockers on your browser it can often interfere with important scripts running properly, resulting into such errors  or failures to load tracks at times. Please disable your adblockers or whitelist Deezer and check again.
• Proxy or Firewalls: If you’re under a corporate environment (computer or network), chances are they have some rules that could be filtering out some elements that impair the functionality of Deezer Desktop, and Web too. Try using a device that’s not under this environment and see if the issue emerges.
• Background Processes: Sometimes you might be having a lot of process running in the background hogging your resources, particularly internet resources - you can check for those and close any process that you do not recognize as legit.

If all the above issues do not solve your issue, please write back here and the team will continue to assist you.