Users faced problems with ride-hailing company Grab's mobile application last night.
The app showed up blank and greyed out at the bottom where the "Book" button usually appears for Apple phones, while a check on Android phones showed the following message: "Sorry :-( Looks like we weren't able to connect to our server. Please try again in a few minutes."
Members of Telegram chat group SgRoad Blocks/Traffic News first reported issues with the app at 8.31pm, with one user claiming "Grab has been down for more than an hour".
GrabCar driver Muhammad Ali, 36, told The Straits Times that he noticed the issue at around 8pm when he was dropping off a passenger.
"I could not end the trip," he said. "I wanted to have a few more trips; now I'm still waiting. I think if at 10pm it's not working, I will go home."
Mr Ali, who has worked with Grab for about a year, said he could have earned about $80 in the 1½ hours that the app was down from 8pm to 9.30pm.
He usually drives his GrabCar from 7.30am to 1pm, then again from 5pm to 10pm. He added that he received an SMS from Grab at 9.36pm informing drivers about the problems with the app.
University student Hazel Ting, 21, said: "It's quite concerning seeing as how Uber is no longer a second option. If the app were to be down again and I need to urgently get somewhere, I might not be able to book a taxi in time."
Grab addressed the issue in a Facebook post at 9.23pm, writing: "Dear customer, we are experiencing a service interruption, which may result in your Grab app not functioning as expected." Its team was "working around the clock to resolve it".
The issue was also experienced in Malaysia, with Malaysian news site The Star reporting service interruptions.
Grab currently offers services in more than 190 cities across Singapore, Indonesia, the Philippines, Malaysia, Thailand, Vietnam, Myanmar and Cambodia.
The firm last week announced it was acquiring American rival Uber's operations in South-east Asia for an undisclosed amount.