This incident has been resolved.
Jan 31, 18:08 PST
Push notification availability was restored to normal at 6:07PM PT. The cause of this issue was that new caching infrastructure had reached its capacity and was not able to evict old entries to make space. We have changed the caching policy and have confirmed that the push notifications service has been restore to its normal health.
Jan 31, 18:07 PST
We are continuing to monitor for any further issues.
Jan 31, 18:06 PST
A fix has been implemented and we are monitoring the results.
Jan 31, 18:04 PST
As of about 5:33 PM PST, push notification reliability has significantly dropped. We are investigating the issue.
Jan 31, 17:33 PST