However, the social media platform did not elaborate on what kind of server configuration change they went through.
A grand jury in NY has subpoenaed information from at least two major smartphone makers about such arrangements with Facebook, according to the Times.
The DownDetector website - one of the internet's most used sources of numbers on outages - showed the number of complaints had peaked at more than 12,000, gradually falling to about 180 in the early hours of Friday morning.
Facebook takes tens of millions of dollars of advertising revenue every day.
Lori Loughlin Released on $1 Million Bond After Alleged College Bribery Scam
John Vandemoor, a former Stanford University sailing coach who worked with Singer, also pleaded guilty to racketeering conspiracy. Nine college coaches, two SAT/ACT administrators, one test proctor, one administrator, and 33 parents are now facing charges.
A Facebook outage in November previous year was attributed to a server problem, and a September disruption was said to have been the result of "networking issues".
The company blamed a change it had made to its system for the outage.
The outage began Wednesday afternoon and triggered a flood of gripes on downdetector.com, which tracks trouble accessing online pages, and on rival Twitter. There were still sporadic problems Thursday morning.
Facebook and Instagram has been coming back online for most users on March 14, but it appears it's not completely out of the woods yet.
Facebook Messenger, Instagram, and WhatsApp were also down for many, and users also reported that logging into other websites with their Facebook or Instagram accounts didn't work.
We've asked Facebook how it intends to resolve its issues with angry advertisers, but did not receive an immediate reply. "We are very sorry for the inconvenience and we appreciate everyone's patience".