During connection to O365, MAPI error gets generated as follows:
Steps you can follow:
1. Upgrade to the latest MNE version
2. Run MNE Pre-Checker, as administrator, to correct any warning/error shown
3. Remove current Outlook and reboot MNE server, and install the current Outlook 2016
(click to run) from the O365 Portal
(If you get same MAPI error, then you might need to remove Outlook and reinstall it)
4. Create Outlook profile if needed (based on the migration account not the migrated user)
5. In the MNE Console, under Exchange section, check if you are supposed to use MAPI/HTTP
or Outlook anywhere(proxy needed)
6. in the MNE Console, under Exchange section, retype the exchange account password.
7. Check if you need to connect to O365, from MNE server, without using any proxy
If needed try to check/reset the proxy:
