Facebook wrote on its Twitter account, Friday evening, that the company is aware that some people are having trouble accessing their apps and products, and that they are working to address the matter as quickly as possible.

Instagram also wrote a tweet apologizing to those having issues and said they are working as quickly as possible to fix the problem.

This comes after Facebook, WhatsApp and Instagram experienced worldwide blackout on Monday, Oct. 4.

Facebook said Tuesday that the main reason behind the outage that occurred Monday evening was a configuration change to the main routers which coordinate network traffic between the company’s data centers.

Facebook’s shares dropped around five percent following the global outage.