TSB has apologised to its customers after they were unable to use its digital banking services on Thursday morning.
It comes after TSB faced an IT meltdown last year which left thousands without access to its online banking services.
The latest problems started on its mobile app and website at about 4am and were fixed three hours later.
TSB said the issue stemmed from routine maintenance scheduled at that time.
People expressed their frustrations over the latest issues on Twitter, with one saying: “Oh here we go again. TSB bank is down again. Time for a switch I think!”
Another said: “#TSB yet again, can not access my online banking, becoming far too common these days. Think a bank change is on the cards.”
Last year’s problems were caused by a botched technology migration attempt.
The bank has seen its ranking fall after multiple IT issues – and was positioned 12th out of 15 UK banks in a recent poll by Ipsos MORI.
A TSB spokesman said: “We are aware of an intermittent issue that affected a small number of customers trying to access their mobile and online banking early this morning.
“We can confirm the problem has now been fixed. We would like to apologise for any inconvenience this may have caused.”
The company has seen a mostly stable service in recent months without only a few minor incidents noted.