MNE data migration logs the following warning and then re-tries migration again:
WARNING: [5022-108-36-80040115]Unable to access free/busy for site '/o=EXCHANGE/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)'
MAPI Error 80040115
MNE uses the pre-exchange 2007 public folder-based method which in some cases can cause a MAPI error.
The loop is caused by parameter "MapiErrorsToRetry" which includes MAPI error 80040115 by default:
Below parameter fixes this issue:
For Exchange 2007/2010/2013, free/busy data is no longer stored in the public folder either accessed via public folder-method. Exchange client (Outlook 2007/2010/2013, OWA) uses Availability Services to render free/busy data in user's calendar view.
The pre-exchange 2007 public folder-based method is expected to be removed in a future release.