Update: Known Error impacting Yammer

Microsoft has restored inbox and feed functionality to the service. Their work to restore real-time notifications continues.

Preliminary root cause: A portion of the infrastructure that accepts and routes incoming connections to the service is degraded, which impacts access to the Yammer site as well as real-time notifications and viewing messages from an email inbox.

More information: Update: Known Error impacting Yammer

Story added 18. July 2017, content source with full text you can find at link above.