Messages failing to send? iMessage down for some users

Users are reporting outages affecting Apple’s iMessage service, with messages sent from iPhone, iPad and Mac failing to send as part of an issue affecting users worldwide.
Verified by The Apple Post, some messages sent through iMessage are failing to be delivered, with the Messages app on iPhone showing notifications that confirm messages are not being sent, with the message thread also showing an error next to recent messages sent during the outage.
Apple’s System Status webpage is yet to acknowledge the apparent outage, but users have been quick to take to Twitter to report the issues, suggesting the issues are widespread.
There doesn’t appear to be a fix for the problems as of yet.