Hi

We have a new Exchange 2013 CU8 deployment, running on Server 2012R2, in co-existence with our existing Exchange 2007.

Users we have migrated to 2013 are having intermittent issues sending emails through ActiveSync. This is on Android and iOS devices. When sending, the messages fail and stay in the outbox. If you go to the outbox and resend, eventually it will be sent. This can take 1 resend or many. Sometimes messages go first time without failing.

The Outlook app for ios and android is not having the same issue, emails are sent fine, however with the stock Email for iOS and Android mail apps, we are seeing this issue. The tracking logs are not showing any failures, only the successful sending.

ActiveSync is published externally through 2 x 2012R2 WAP servers, connecting to a VIP on jetnexus ALBs, with the exchange services presented through that. We have tried restricting the VIP rules to just one server to rule out persistence issues, with no success.

Outlook and OWA are functioning correctly with no known issues.

Any ideas, please?

• Edited by voyco 20 hours 10 minutes ago

This also occurs when connecting direct to a server with activesync, so that rules out our load balancers and indicates even more that Exchange is the issue.