Safaricom's mobile money transfer service M-Pesa was on Monday morning temporarily unavailable.
The telecommunication firm confirmed the glitch and said it is working on restoring the service.
The latest malfunction comes a day a concerned ICT Cabinet Secretary Joe Mucheru asked the Communications Authority of Kenya and the Central Bank of Kenya to investigate the recent spate of M-Pesa services outage and its effects.
The two bodies are to prepare a report that would include remedial measures to be taken by Safaricom.
Inconvenienced subscribers took to Twitter on Monday to demand for an explanation from the firm.
Abu Salaam tweeted; "Mpesa delays in early Monday morning? what da hell is going on @safaricom_care."
Njihia Kelvin wrote; "@Safaricom_Care I need to pay someone urgently. Guys if you are hacked just say tired of this and you can't even apologize."
Victor Peace questioned; "@Safaricom_Care why you messing us up. Stuck in a petrol station because mpesa has delays. Could you communicate earlier?"
Safaricom apologized to the customers with the response; "Apologies for the experience. We are working to resolve soonest possible. ^PI."
After two hours the firm notified its subscribers that the services had been restored.
The service had on Saturday experienced database hitches that were resolved but went down again in hours.