Spotify was knocked offline for a few hours this weekend after a data centre it uses overheated on Saturday.
Spotify spokesman Andres Sehr apologised for the outage in a blog post, explaining that the data centre was hit by a power outage.
"The backup power kicked in as planned, however, one of the big air conditioners in the data centre did not start properly," he said.
"Heat is a major issue in large data centres and without this cooling unit the temperature rose very quickly and our servers shut down to protect themselves from over heating," he said, adding it took a few hours to get the system up and running because of its complexity.
Sehr said everything was working correctly again. However, he warned that "a few" premium users - those who pay to use the service in offline mode and without ads - may see some "billion anomalies". He said Spotify would contact anyone affected by the problem.
In addition, Sehr advised anyone still having trouble with Spotify to reinstall it.
