Singapore's M1 has launched two separate probes into this week's mobile network disruption - the company's third in 13 months – and is offering free calls to customers as an apology.
Some of M1's mobile customers were intermittently unable to make voice calls or send and receive SMS for a five-hour period on Tuesday.
In a statement, M1 said a preliminary investigation has pinned the fault on a glitch in the company's call processing software. This bug prevented customers' devices from registering on its mobile network.
CEO Karen Kooi said the company will proceed with a full investigation, and has also appointed an independent expert to conduct a network architecture and connectivity review.
“We appreciate our customers’ understanding, patience and support, and we would like to offer our customers one day of free local mobile calls, local SMS and MMS this Sunday as a goodwill gesture,” she said.
M1's mobile network suffered a six-hour outage in December, and regulator IDA Singapore fined the operator a record S$1.5 million ($1.2 million) over a nearly three-day disruption to the operator's 2G and 3G networks in January.
IDA has announced it will be conducting its own investigation into the cause of this latest outage “before determining the appropriate course of action.”
M1's experience shows that as the complexity of the modern network increases, so too does the potential for something to go wrong.