We have a case for it:13-12-2023 07:12:05 :: Processing mailbox xxxxxx failed with error: There is an error in XML document (1, 5332).. The specified type was not recognized: name='SharingMessage', namespace='http://schemas.microsoft.com/exchange/s ... 2006/types', at <Message xmlns='http://schemas.microsoft.com/exchange/s ... 2006/types'>. :: 0:00:24
13-12-2023 07:13:29 :: Processing mailbox xxxxxfailed with error: There is an error in XML document (1, 115683).. The specified type was not recognized: name='SharingMessage', namespace='http://schemas.microsoft.com/exchange/s ... 2006/types', at <Message xmlns='http://schemas.microsoft.com/exchange/s ... 2006/types'>. :: 0:00:07
13-12-2023 07:13:53 :: Processing mailbox xxxxx failed with error: There is an error in XML document (1, 59061).. The specified type was not recognized: name='SharingMessage', namespace='http://schemas.microsoft.com/exchange/s ... 2006/types', at <Message xmlns='http://schemas.microsoft.com/exchange/s ... 2006/types'>. :: 0:01:41
Case #07047525
But we find it quite hard just to tell all of our customers, "to fix it yourself".
So far we have not been able to find what they have in common. Because its not all mailboxes within the same tenant, and its not all tenants..
Should be noted, that we are running VBO 7, and the customers are not even sharing the same VBO or backup proxies. (All of them same version, however.)