Resolved
We were encountering intermittent issues with all of our email provisioning servers because of which you may have faced the below error while trying to add users/modify existing user details via the API/email dashboard:
Missing com.openexchange.admin.rmi.OXUserInterface instance.
The
issue was identified by the System Administration Team and fixed on top
priority. The issue was related to the database outage we faced last
night, details of which can be found here.
A few incorrect configurations resulted in calls being made to an incorrect database. This has now been corrected and services have been restored.
Posted September 19th, 2017 10:48 am GMT 
Affected Services
- Email Hosting
Affected Servers
- oxdb1-ee.mailhostbox.aus-tx.colo
- oxdb2-ee.mailhostbox.aus-tx.colo
- oxdb3-ee.mailhostbox.aus-tx.colo
- oxdb4-ee.mailhostbox.aus-tx.colo
- oxdb5-ee.mailhostbox.aus-tx.colo
- oxdb6-ee.mailhostbox.aus-tx.colo
- oxdb7-ee.mailhostbox.aus-tx.colo