A global outage to Microsoft’s systems have caused delays in offices, airports, and more around the world.

The cybersecurity company CrowdStrike was performing a routine update when the outage occurred, but officials are still unsure of the root of the problem.

Many believed at first that it was a cyberattack, but that has since been ruled out.

The biggest issues have been felt at the nation’s airports, where Delta, United, and American Airlines have all grounded their flights, causing major delays and traffic at airports.

Businesses have experienced network issues, system crashes, and more.