When a user attempts to SSO into the 365 they're presented with a blank white page and are unable to progress any further.

Root Cause

The browser cannot resolve ‘’. This is a problem with the lightspeed filtering tool.

It had started categorising this Microsoft address as malware:


The URL needs to be accessible via lightspeed.

The address has been listed on their page before -, however from a quick search it reveals that it has been blocked by various filtering systems before.

Change forwarders to