Company B who we hosted email on our Exchange 2007 server/domain moved there email to Office365, since I disabled there email account users in A are unable to send mail to them , and get: #550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ##
I deleted the Outlook Cache entries, still an issue. Outlook Web Access works as well as recreating an Outlook 2010 profile.
What is a server side resolution - send connector? thanks.