On Wednesday evening, AT&T wireless customers across the nation couldn't get connected to 9-1-1. Some callers could only get a busy signal.

Now the FCC is investigating what happened.

Within minutes, San Antonio police and first responders across the country sent out alerts on social media notifying the public of the outage.

AT&T experienced a nationwide outage affecting 9-1-1 calls.

"When we tested it out using an AT&T carrier, we were getting a busy signal," said Sgt. Jesse Salame of the San Antonio Police Department.

In a statement, Ajit Pai, chairman of the Federal Communications Commission, said that he launched an investigation into the 9-1-1 outage:

"Every call to 9-1-1 must go through. So when I first learned of yesterday's outage, I immediately directed FCC staff to contact AT&T about it and the company's efforts to restore access to emergency services to the American public,” the statement read. “Additionally, I announced last night that I have directed commission staff to track down the root cause of this outage."

"Thankfully we didn't have anybody that we know about that said they absolutely needed to get through to 9-1-1 during that period," Sgt. Salame said.

Police told KENS 5 that the outage lasted for a matter of minutes. They informed the public once calls were back up and running.

AT&T sent a statement to KENS 5 which read:

"We take our 9-1-1 obligations to our customers very seriously and will be sharing additional information with the FCC."

If a similar outage happens again, San Antonio police suggest following them on social media and saving their non-emergency line (210-207-SAPD) to your cell phone.

Police also recommend saving the number to your police substation.

If you aren't sure which substation covers your area, visit this link to find out more.