UPDATED | July 31, 2017, 5:13PM

NORTH TEXAS (CBSDFW.COM) – Residents in at least three North Texas cities had issues reaching 911 Monday morning. The issues were fixed Monday afternoon for the cities of Plano, Garland and Rowlett.

Two of the problems involved mobile networks, the other a citywide outage.

READ MORE: COVID-19 Omicron Variant Confirmed In 2 North Texas Patients By Frisco Lab

T-Mobile wireless customers in the city of Plano experienced problems making 911 calls. Before sunrise Monday a supervisor in the 911-call center said crews were working to fix the issue. The problems started around 6:45 Sunday evening, that’s when T-Mobile customers in Plano started getting a “busy” signal when calling 911.

At 3:45 p.m., the city of Plano tweeted that 911 services were restored for T-Mobile customers and that Frontier Communications repaired the network issue that caused the problems.

The city had posted messages to Twitter and Facebook Sunday night alerting T-Mobile users that they were “experiencing some issues.”

It was earlier this year when the city of Dallas dealt with its own problems with the T-Mobile network. So-called “ghost calls”, ones caught in a loop lacing calls repeatedly, were flooding the 911-call center, overwhelming call takers and leaving some people with actual emergencies on hold. It isn’t known if Plano experienced the same kind of issue.

Susan Rodriguez, a spokesperson for Plano 911, said, “Anytime that someone can’t dial 911 and get through that’s a concern for us. We notified them (T-Mobile) as quickly as possible, so they can get the issues resolved so we can get back to business as usual.”

Residents in Rowlett were also having 911 issues. Around 5 a.m. the police department sent out a tweet explaining that 911 lines in the city were completely down.

READ MORE: Plano Takes Next Step Toward Farm-Inspired Mixed-Use Development, Haggard Farms

The 911 system in Rowlett was repaired after police tweeted a confirmation just before 3 p.m. Monday.

Rowlett PD Public Information Officer Cruz Hernandez explained to CBS 11 News that, “Last night about 10 p.m. or so our 911 calls got switched to Garland.” Cruz said when there’s a problem or issue the system automatically routes emergency calls to the neighboring city.

Hernandez said that around 1 a.m. the dispatch center began receiving calls that were silent or only had static on the line. “There was no communication,” he said. “We couldn’t hear them, they couldn’t hear us and there was no data on the screens.”

Officials in the city of Garland said they were also having problems with people not being able to reach the 911 center if they are calling from a mobile phone. Garland police spokesman Lt. Pedro Barineau said the problem started Sunday afternoon when 911 call takers either heard a loud buzz or complete silence when they answered a call.

Garland Police sent out a tweet at 2:47 p.m. to announce that 911 problems were resolved and back to normal.

Barineau said the public wasn’t notified because operators were always able to call the number back and make contact with the initial 911 caller.

MORE NEWS: 300+ Astroworld Festival Lawsuits To Be Handled By 1 Texas Judge

City officials in both Rowlett and Garland said the problem was with a group of lines serviced by Frontier Communications that route calls to the 911 centers.