Royal Bank of Scotland customers faced more frustration today after they found themselves locked out of the bank's mobile app.
Around two million people use the service and the problem has also affected customers of Natwest and Ulster Bank, which are part of the same group.
All the banks belong to RBS Group, which apologised to customers and said it was working to fix the problems which have prevented people from logging in.
The hitch is thought to have started at around 7am and is the latest technical problem to have beset the group, starting with a huge IT meltdown last summer.
A spokeswoman for RBS could not say how many customers have been affected, although both personal and business users have been hit by the problems, which have struck just before the busy Easter weekend as people make plans to get away.
There are more than two million active users of the app among RBS and NatWest personal banking customers alone, with 13 million log-ins taking place each week.
The latest IT issues come just three weeks after a hardware fault prevented RBS Group customers from using cash machines and also affected online and telephone banking services.
The group took a £175 million hit as a result of last summer's IT chaos which left NatWest, Royal Bank of Scotland and Ulster Bank customers locked out of their accounts. The bulk of the redress costs related to Ulster Bank, where the problems took weeks longer to clear up.
A statement from RBS Group said: "We are aware of a technical problem this morning which is preventing customers from logging in to our mobile banking applications.
"We are working to fix the problem and apologise to customers for the inconvenience caused. No other systems are affected."
The collapse also comes just weeks after the bank unveiled a new mobile banking feature for RBS/NatWest customers called Pay Your Contacts, which allows them to send payments of up to £100 to anyone with a Visa card, by entering their mobile number.
Last October, NatWest had to suspend another feature on its mobile phone app called GetCash, after the service was subject to a spate of "phishing" attacks by fraudsters.
The GetCash service, which allows customers to withdraw cash without using a debit card, was later re-instated after security was beefed up.
Customers vented their anger at being let down again by the group's technology.
One Twitter user wrote: "No access to my iPhone app think it's time to change banks!"
Another said: "The one day I'm desperate to use the NatWest app it's broken, get it together people."
Pointing out the bank's previous IT problems, another Twitter user wrote: "How many chances do they want? After last time you would think they've learned."
A spokeswoman for consumer group Which? said the problems will raise wider questions about "how robust and up to date banks' IT systems are".
She said: "Consumers and businesses alike rely on mobile banking services to access their accounts and consumers will rightly want to be assured that their money is accessible and safe at all times."
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereComments are closed on this article