Cannot connect to Sainsburys.co.uk

When I try to browsw to sainsburys.co.uk I get the following response: 403 ERROR
The request could not be satisfied.
Request blocked. We can’t connect to the server for this app or website at this time. There might be too much traffic or a configuration error. Try again later, or contact the app or website owner.
If you provide content to customers through CloudFront, you can find steps to troubleshoot and help prevent this error by reviewing the CloudFront documentation.
Generated by cloudfront (CloudFront)
Request ID: GwpIAJbXVnfzj-uTvL7rMP_d1umC3Ei8SjN0wp_LWXdy39BZOTcdAg==

This doesn’t happen with any other site – can anyone suggest a solution?