I created a dynamic DL using:

Set-DynamicDistributionGroup “NAMEOFDL” -RecipientFilter {(RecipientType -eq ‘UserMailbox’) -and (PrimarySmtpAddress-like “*domain.com”)}

But messages sent to it wouldn’t be delivered, and a message trace showed:

“Reason: [{LED=250 2.1.5 RESOLVER.GRP.Expanded; distribution list expanded};{MSG=};{FQDN=};{IP=};{LRT=}]”

With Microsoft support’s help, it was discovered that the documented method doesn’t work, but this does:

Set-DynamicDistributionGroup “NAMEOFDL” -RecipientFilter {(WindowsLiveID -eq ‘*@domain.com’)}