UK bookmaker William Hill is struggling to reboot its website following a “sophisticated’ distributed denial of service (DDoS) attack on Tuesday.

The Williamhill.co.uk website went dark Tuesday afternoon, preventing bettors from placing wagers on the evening’s UEFA Champions League matches featuring Arsenal and Manchester City. The company said the site had been laid low following a “sophisticated” DDoS attack by unspecified “third parties.”

The company claimed that while “the attempt at disruption is ongoing,” its technical teams were able to restore services by Tuesday night. However, Hills’ official Twitter feed later confirmed that “we’ve got some services back but we’re still not at 100%.” As of Wednesday afternoon, the company says connectivity remains “intermittent.”

For the moment, Hills is directing customers to use its betting app, while reassuring customers that the site’s problems do not extend to any “security related issues.”