Tenant Cant Access Public Folder via EWS: Can't connect to the mailbox ...

[vlw007]

We have gotten this message messages on dozens of tenants on a random basis:

the specified object was not found in the store., Can't connect to the mailbox of user Mailbox database guid: 65ba9b0a-dca4-4b0c-98e1-7db303ee3fce because the ExchangePrincipal object contains outdated information. The mailbox may have been moved recently.

Access using EWS Editors yields the exact sames message that our app gets. Users in the tenant can access their public folders via Outlook

Usually this message goes away after a week or so and access to the public folder resumes.

For one particular tenant, they had full access to their public folders via EWS. It was working for several months. Then it stopped working on Sept 22. We reported this issue to MS Support and have not gotten any response.

What can we do to resolve this?

[kb99]

we are seeing similar issues as well for some exchange accounts. It appears to be intermittent across mailboxes. Some days we can connect ok but other days we get the error above on some mailboxes.