Garmin users across the UK have been unable to sync their data since their online Connect service went down this morning (Friday, July 24).

The smartwatch maker has been forced to shut down its online services and call centres, and an error message has appeared on its website.

Why isn’t Garmin working?

The US-based company shut down its official website and all customer services, including phone lines, online chat and email, after an issue affected its internal network and production systems.

The outage began early in the morning in the UK and is 'ongoing' at the time of writing.

The issue has extended its impact to owners of Garmin watches, as it shut down the Garmin Connect service, leaving users unable to sync their sports data through the mobile app.

It also means users cannot access a range of features on their Garmin devices, such as creating new running or cycling routes, or sharing activities on services such as Strava.

However, the devices will still continue to collect data while they are being used, meaning any information gathered during the outage will be recorded and can be uploaded when services are back up and running.

The company warned users of the issue in a post on Twitter and apologised for the inconvenience, although it has not confirmed what has caused the outage.

Garmin said: “We are currently experiencing an outage that affects Garmin.com and Garmin Connect.

“This outage also affects our call centres and we are currently unable to receive any calls, emails or online chats. We are working to resolve this issue as quickly as possible and apologise for this inconvenience.”

What caused the outage and when will it be back online?

Garmin is yet to confirm what has caused the issue with its systems, but it is thought to be a result of site maintenance.

However, other reports have suggested it could be because of a ransomware attack.

Taiwanese tech news site iThome shared an internal memo from Garmin’s IT staff to its Taiwan factories announcing two days of maintenance on Friday and Saturday, which sources told the site was caused by a “virus”, The Guardian reports.

It is not known if the supposed attack has caused any customer data to be lost or stolen.

While Garmin has confirmed the outage has affected all of its online services, it is yet to give an indication as to when its services will be back up and running.