Long queues developed as motorists tried to pay to get out of the Fishergate shopping centre car park.
Two pay machines stopped working yesterday afternoon.
One was repaired yesterday, the other was due to be back up and running again today, said management.
Keith Mitchell, general manager of the Fishergate Centre, said: We have four pay stations. Two machines went down yesterday. We lost connection with the server.
“Engineers were called, they provided quite an urgent response.
“One machine became operational again yesterday so we had three, we’re hoping to get a fourth machine into operation later today.
“There were a large number or people because they lost service at the back end of the day, about 3pm. People were leaving and it created a backlog.”
He praised centre staff for doing a good job, adding: “We explained what it was and the majority of people were understanding and had empathy and sympathy.
“Normally we would have enough capacity. It created a short-term issue with delayed payments.
“These things try and test us. Staff responded as best they could.
“We apologies. It was a one off and shouldn’t happen again.”