After experiencing technical difficulties Friday, the Signal messaging app appears to be back up and running. The company tweeted Saturday night that it was “back,” although added that some users may still see error messages in their chats. The company didn’t explain what caused the outage.

For users still be seeing error messages in their chats — which the company said was a “side effect” of the outage that began around 11:30AM ET Friday— Signal tweeted that those messages do not affect security, rather that you may have missed a message from another user. This will be fixed in the next app updates, the company said.

It offered two fixes if users want to clear the error messages manually: On Android, tap the menu in the top-right corner and choose “reset secure session.” For iOS users of Signal tap the “reset session” button located below “received message was out of sync.”

Signal allows secure and encrypted video, voice, and text communication, and in the past weeks has seen a surge of new users to its app, after CEO Elon Musk tweeted his recommendation, and as rival service WhatsApp unveiled a confusing new privacy policy, which it’s now pushed back several months.

During the outage, the Signal tweeted that it was “working as quickly as possible to bring additional capacity online to handle peak traffic levels.”

The company did not immediately reply to an request from The Verge for further comment on Sunday.