Lately I came across to a new issue in Outlook when accessing Legacy Public Folder.
In order to access legacy PF in coexistance exchange 2016/2013 – 2010 you have to configure Proxy mailboxes on mailbox databases as described here.
Now autodiscover will return the Public folder proxy mailbox . in Test e-mail autoconfiguration under XML tab on the bottom
If the UPN of this proxy mailbox is different form the UPN of the mailbox and it is for example internal .local outlook will not display the PF. No error messages. Public folder root is visible but cannot expand.
It seams that Outlook 2016 is creating autodiscover request for the PF Mailbox and when this Mailbox has .local domain cannot resolve it.
There is no such issues with older outlook versions.