IPs and referring URLs
Authentication problems (i.e. not being able to access subscription content) can sometimes be caused by a mismatch between the IP address we have registered for a subscribing institution and the actual IP sent to our server, or because the web browser is not passing a referring URL to our access control system.
The link below will report the IP address you are coming from, as well as whether your browser is returning a referring URL. To ensure that current values are returned, press refresh/reload (Ctrl+F5 on PC or Apple+R on Mac) while viewing the IP check page.
If no Referring Address value is present on the IP check page (the value should be the URL of this page), the referring URL is being blocked by your local firewall, antivirus software or browser.