“We don't know what's causing the disruption or when it will be resolved,” a T-Mobile spokeswoman said. “We're getting similar reports from several regions.”
Many Deutsche Telekom customers were no longer reachable on their mobile phones from 4 pm. Outgoing calls on the T-Mobile network were occasionally possible, but they were delayed going through and often there was no reception at all.
T-Mobile SMS and data services were also affected by the outage.
Deutsche Telekom had around 40 million T-Mobile customers in 2008.