The system underwent a £70 million upgrade in May, which involved replacing conveyor belts and chutes with 2.4km of track and 180 automated carts.
An airport spokesperson, who apologised for the disruption and told the BBC the problem had been fixed, said they believed the system had suffered a power issue.
"Contingency measures were immediately put in place with our airlines to mitigate disruption and manually process baggage while engineers worked to fix the issue," they added.