Lloyds has blamed the website outage which marred the re-launch of TSB on a data centre hardware malfunction.
Customers had trouble accessing TSB's website this morning, with many taking to Twitter to complain that they were unable to access internet banking.
A Lloyds spokesperson told Computerworld UK that the outage was related to a hardware failure with some of its networking equipment.
"The outage was caused by a problem with a routing mechanism in one of our data centres," the spokesperson said.
"I can confirm that all systems have been up and running since this morning and the problem was intermittent for a couple of hours."
Earlier today a Lloyds spokesperson confirmed that customers were temporarily unable to access their online accounts following the fault.
"We are experiencing an issue with our internet banking service this morning, which has affected the ability of some customers to log on successfully," a statement read.
"We are working to resolve this as quickly as we can and we apologise to customers for the inconvenience this will have caused. Our branches, telephone banking and cashpoint facilities have not been affected in any way."
The TSB website went live in August. However, customers were only able to log into the site from 8 September, ahead of the full launch of the bank today, as it separates from Lloyds to operate under its original name. The accounts of five million customers were being automatically transferred from Lloyds to TSB.
Commenting on the outage Michael Allen, Director of APM at Compuware, said that the bank should have done more to prepare for any problems arising as TSB split off from Lloyds.
"Given the uncertainty that the split has caused for customers, for them to then not be able to get into their accounts this morning will have created unnecessary stress for thousands, if not millions, of customers," he said.
"Banks need to manage the risks associated with technology performance in a more proactive way, with early warning systems that can alert them to any potential problems before they create chaos for their customers.
"For example, monitoring these services from an end-user's perspective to see how they perform in the real world will identify any weak spots and inefficiencies and enable them to be rectified ahead of demand hitting, rather than after the complaints have begun to pour in."