There are two possible explanations for this. Please contact us if neither resolves the problem:
1. Check your security settings. Browsers only permit strict-origin-when-cross-origin policy referer links – see e.g. https://docs.microsoft.com/en-us/microsoft-edge/web-platform/site-impacting-changes . In the first instance ask your IT team to add a meta referer into the head portion of your site.
2. If you have recently changed your network settings, your IP range may have drifted. Please contact us to update your IP range.