so far yes.
I had to exclude one specific mailbox, as this was extremly slow, and does a full backup each time (10GB) instead of incr. Support is looking into this one.
I also had to decrease number of threads on the proxy from 10 to 2 - otherwize it would be sooo sloooow. Now i have set threads to 4.
But i wonder, why i got those weird errors:
04-10-2017 06:00:00 :: Processing data from remote server outlook.office365.com failed with the following error message: [ClientAccessServer=AM5PR0601CA0025,BackEndServer=dbxpr06mb288.eurprd06.prod.outlook.com,RequestId=703579b2-7353-4fe7-ad02-c0f65679e9a6,TimeStamp=10/4/2017 6:00:02 AM] [FailureCategory=WSMan-Others] The EndpointConfiguration with the http://schemas.microsoft.com/powershell ... t.Exchange
identifier is not in a valid initial session state on the remote computer. Contact your Windows PowerShell administrator, or the owner or creator of the endpoint configuration. For more information, see the about_Remote_Troubleshooting Help topic.
29-08-2017 14:42:33 :: Processing mailbox XXX failed with error: Invalid Exchange Server version
07-08-2017 06:34:10 :: Processing mailbox XXX failed with error: Failed to get folder properties. SOAP header Action was not understood. :: 0:00:55