Auto discover slowness Outlook 2016

Microsoft has a vague article about it: https://support.microsoft.com/en-us/kb/2212902

From the list of keys they have to our disposal following is to our experience:

·         ExcludeHttpsRootDomain – no affect

ExcludeHttpsAutoDiscoverDomain – no affect

·         ExcludeScpLookup

ExcludeLastKnownGoodURL

After I added ExcludeScpLookup and ExcludeLastKnownGoodURL auto discover started working fast. One of these two keys added to the registry with the value of 1 is the fix of the issue.

Giving Helpdesk Full access to Rooms

Get-MailBox -Resultsize Unlimited | Where-Object {$_.ResourceType -eq "Room"} | Add-MailboxPermission -User Helpdesk -AccessRights FullAccess

Helpdesk - security group name.