UK challenger bank Monzo addressed recent issues concerning its bank transfer services. The digital banking platform reported that on May 30th, around a quarter of bank transfers into Monzo accounts were failing or delayed by several hours and bank transfers from the Monzo accounts were delayed by a few minutes. The Monzo team further explained:
“During this time, you might’ve had trouble getting payments from other banks, had payments into your account take a while to arrive, or seen bank transfers arrive in your Monzo account then get reversed later. This was down to a technical problem at the company we use to connect to Faster Payments, the system that powers most bank transfers in the UK. This is totally unacceptable and we’re really sorry. During and since the issue, we’ve been making sure you haven’t been left out of pocket by what happened, by providing access to emergency money while waiting for a transfer, or covering any fees you’ve been charged because of delayed payments.”
The Monzo team also revealed more details about the error and how the system was fixed:
“Our Gateway provider found a bug that caused one of their systems to get stuck in a state where it corrupts all messages passing through it. They deployed a fix for this on Thursday the 13th of June. The bug was in a computer program the Gateway uses to translate payment messages between two formats. When the program was operating under load, the system tried to clear memory it believed to be unused (a process known as garbage collection). But because it was using an unsafe method to access memory, the code ended up reading memory that had already been cleared away, causing it not to know how to translate the date field in payment messages.”
In regards to how they plan to avoid the same error in the future, the Monzo team added:
“We’re continuing with a project to bring our Faster Payments Gateway in house, so we don’t have to depend on a third party to handle bank transfers. This is a fairly large project, with long timescales. This kind of project usually takes over six months, from starting to going live. Fortunately, we started this process several months ago, when we experienced a number of smaller-scale incidents. We’re estimating that we’ll switch to our own Faster Payments Gateway in November 2019.”