From 01:02 PM to 4:16 PM PST yesterday, Targeting of Audiences based on Optimizely Classic Uploaded Lists was not working due to an outage in one of it's internal components. During this time, targeting calls for any active experiments based on Optimizely Classic Uploaded Lists were returning 500s.
During this time interval, if there were any active experiments based on Classic Uploaded Lists, then the Results for those experiments would show no traffic.
Note that Optimizely X Uploaded Lists Targeting (through List Attributes), currently in Beta, was unaffected. We are sorry for the inconvenience this has caused, and are making improvements to prevent this occurrence in the future.