I have an issue between Exchange Server 2010 and Office 365; when I tried to send an email between office 365 and on premise Exchange Server 2010 or vice versa the emails stopped in Queue with this error "451 4.4 0 primary target ip address responded with 421 4.4 2 connection dropped due to socket error", even Hybrid Configuration Wizard failed to sync with O365, any help will be appreciated


