ST. PAUL (AP) -- Authorities and telecommunication officials are continuing to investigate what caused a widespread 911 service failure in Minnesota.

Counties and cities scrambled to broadcast alternative emergency phone numbers through social media and other means during the hourlong outage Wednesday.

CenturyLink spokesman Frank Tutalo says that the company is investigating the outage. He did not immediately respond to messages Thursday seeking comment on how many agencies were affected and a timeline for the investigation.

The Minnesota Department of Public Safety says that the outage was resolved by 5:30 p.m. on Wednesday.

The Federal Communications Commission fined CenturyLink $16 million for a six-hour 911 outage in 2014 that affected 10 million people in Minnesota, Washington and North Carolina.