As described by Microsoft in this article, Office 365 will no longer support RPC over http as of October 31, 2017:
This is significant for longtime Epicenter users because, for about two years, Outlook 2013 *only* supported RPC over http. Therefore, there are many Epicenter systems that are configured for the deprecated protocol.
To resolve the problem:
- You need to run Outlook 2013 or Outlook 2016 with the latest updates. Both of these support the newer protocol. Outlook 2010 is no longer supported by Epicenter for use with Office 365.
- If you've been running Epicenter for a couple of years, you may have configured Outlook to force RPC usage because earlier versions of Outlook 2013 had a bug regarding MapiHttp.
This article describes how to remove the relevant registry entry:
- After making that change and restarting Outlook, make sure that Outlook is connecting using HttpMapi. You can do this by opening the Outlook Connection Status by Ctrl-Clicking the Outlook icon in the taskbar. If Outlook is still connecting with RPC, close Outlook, create a new profile, and make it the default.
After making the changes above, there is only about a small chance you'll need Build 438 to fix an ecNoReadRight error. You'll be offered this update automatically if your Technical Support Subscription is up to date.