DBS Bank cited its “access control servers” as the main reason for the two-day disruption, which made it difficult for many customers to access their accounts.

The Singapore-based bank has been forced by local regulators to investigate what caused the service’s outage.

The outage was first reported on Tuesday morning when customers had difficulty accessing the online and mobile services of their DBS.

DBS claimed that they were able to restore services on Wednesday morning, although DBS users still reported access difficulties even after the bank’s announcement.

DBS released an update late Wednesday night saying its digital services were “returning to normal” and the situation was being monitored to ensure the services were fully operational again.

The bank remained vague on what caused the problem with its access control servers or whether its systems were the victims of a cyberattack.

Meanwhile, the Monetary Authority of Singapore (MAS) said in a statement that it would take the necessary actions after DBS had completed its investigation.

Together with its subsidiary POSB, DBS has around 5 million customers in Singapore.