A screen displays the Instagram logo during a presentation in New York, Dec. 12, 2013. REUTERS/Lucas Jackson

Photo-sharing app Instagram is apparently down, showing a "5xx Server Error" notice--and users are going crazy on Twitter for not being able to share their selfies.

The app’s site displayed a “Server Error” notice on Monday afternoon:

Instagram app down 5xx server error
Instagram app and site is down, displays "5xx server error." Instagram, screenshot

While on the iOS app, Instagram could not refresh the home feed or profiles. However, some users’ stories could be seen.

Users went on Twitter to announce Instagram wasn’t working for them:

Update, 2:10 p.m.: Instagram tweeted that it's aware of the problem and is working on a fix.

The problem seems to be international, since people in the U.S., France, Argentina and other countries reported having trouble with the Instagram not working.

We’ll update when we find out what went wrong.