A fault with a Isle of Man landline network, which meant 999 calls could only be made on mobile phones, has now been resolved, Manx Telecom said.
The operator said the issue, which began at 08:35 BST, was caused by "failed ISDN circuits".
The "outage" affected government departments, Noble's Hospital, the 999 service, Manx Telecom HQ and a number of other businesses, a spokesman said.
Manx Telecom apologised to all customers for the inconvenience.
Its mobile network was not affected.