TSB customers complain of fresh IT problems
TSB customers woke up to another IT failure at the beleaguered lender on Monday, with many unable to access their accounts.
Hundreds took to social media to complain about issues including "duplicate transactions", while TSB said that it was working to fix the issue.
TSB said in a tweet: "We're aware that some customers are having issues this morning using internet banking, the mobile app and telephone self service.
"We are currently working to fix this issue. Please accept our apologies for any inconvenience caused."
TSB undertook planned maintenance on its website on Friday, but insisted Monday's issues were unrelated.
The latest problems come after up to 1.9 million people using TSB's digital and mobile banking found themselves locked out of their bank accounts earlier this year.
It was triggered by a migration of customer data from former owner Lloyds' IT system to a new one managed by TSB's current owner Sabadell in April.
A TSB spokeswoman added: "We're really sorry that some of our customers are experiencing intermittent issues with online and mobile banking.
"There was an issue yesterday afternoon which was resolved, however customers may be experiencing a slowness in service.
"Customers are still able to use their cards as normal. We'd like to apologise for any inconvenience this may cause."
TSB's failures have drawn strong criticism from politicians, including those on the Treasury Select Committee who have been scathing in their condemnation and called for TSB's chief executive, Paul Pester, to be sacked.
TSB's board and Sabadell have fully backed Mr Pester to continue in the role.
It was reported last month that TSB is to double the size of its customer complaints team to 500 as the bank ramps up efforts to address customer grievances.
The troubled lender is recruiting hundreds of extra staff as it looks to address the 135,403 complaints which had been logged as of July 25.