Many customers woke up to an error message when they tried to access one of the banking apps or online services.
There have been reports of some Lloyds and Halifax cash machines also appearing to be offline in an apparent network glitch.
Problems reportedly began at around 6.30am on the morning of Thursday 18 November 2021.
Thousands of people had been experiencing trouble accessing their Lloyds or Halifax banking app, with the latter stating "N/A", meaning not applicable or not available.
Twitter was awash with complaints from people unable to check their bank accounts or access cash at ATMs.
Lloyds replied to many, posting: "We know some of you are having issues with Internet Banking. We’re sorry for this. We’re working to have it back to normal soon."
While Halifax were also replying to customers: “We know some of you are having issues with Internet Banking. We’re sorry for this. We’re working to have it back to normal soon.”
People were still experiencing problems at 10am this morning, with no update as yet as to what was causing the problems.