We have see an issue with SalesLogix v8.0 and v8.1 web clients where randomly all users are bounced due to an IIS service Issue. After looking into the SalesLogix logs we found the “authentication token is invalid” error repeatedly. While this error usually is indicative of a bad logon attempt in this case it was a by product of the IIS service dropping. At this time McAfee does not have a hot fix so SalesLogix Web admins should run the McAfee Profiler and exclude the W3WP.exe and all SalesLogix files.
Here is the post on the McAfee community.