CenturyLink customers have been experiencing outages since early Thursday. "The CenturyLink service outage is therefore completely unacceptable, and its breadth and duration are particularly troubling".
A nationwide outage for CenturyLink customers continues into its second day, including affecting 911 calls.
The Monroe, Louisiana-based telecommunications company did not immediately respond to a request for comment on the FCC investigation or provide information as to how many customers were affected.
The commission's Public Safety and Homeland Security Bureau will investigate the cause and effect of the outage, he said. Other areas of the country that also experienced 911 outages included parts of Missouri, Idaho and Arizona.
Ruth Bader Ginsburg out of hospital following cancer surgery
The projected date of Ginsburg's discharge from the hospital and her return to the court are unknown at this time. Ms Ginsburg , 85, had surgery to remove two cancerous nodules from her left lung in NY on Friday.
Police and fire departments throughout the state took to social media to alert followers to the problem, which was causing some 911 calls made from landlines and cellphones to not go through to the appropriate dispatchers.
Idaho Emergency Office Management Director Brad Richy says he didn't receive any reports of 911 service failures, but some state offices lost phone service.
At North Colorado Medical Center in Greeley, Colorado, doctors and nurses for a time had difficulty accessing patient records. Whether you're in a vehicle crash, a burning building, or facing a serious medical problem, the last thing you want to hear when you dial "911" is a busy signal.
CenturyLink said it "discovered some additional technical problems as our service restoration efforts were underway". Verizon said CenturyLink helps handle wireless network data traffic for Verizon and other wireless providers.