Japan’s online bank transfer system is experiencing glitches that are disrupting cash remittances at MUFG Bank Ltd. and 10 other lenders.

MUFG said there are troubles at the Zengin System involving money transfers to other banks, preventing some transactions. The core unit of Mitsubishi UFJ Financial Group Inc. was also unable to receive funds sent from other lenders, it said on Tuesday morning.

A spokesman at the Japanese Bankers Association, which operates the Zengin System, said the glitches are affecting 11 banks, adding the issues emerged after the replacement of relay computers during the long weekend that lasted through Monday.

As a result, others including Mizuho Bank Ltd. are having difficulties transferring money to and from the affected banks. It’s unclear when the system will return to normal operation.

The Zengin System is a nationwide online network for banks handling domestic transfers.