My outlook account at work is a member of a group called GraphTest which has email address GraphTest@companyname.net.
I'm trying to use the graph explorer to access mail in that group's inbox.
When I run the query https://graph.microsoft.com/v1.0/users/graphtest@companyname.net/messages I get the error message
Group Shard is used in non-Groups URI.
When I replace graphtest@companyname.net with my own email it works. Also I've consented to the permissions Mail.Read and Mail.Read.Shared.
What does this error message mean, and how can I fix it?