for the past one week we have not been able to recieve nor send mail within/outside our network. from the event log if find the error message below. i have check our firewall for the closed ports and they are ok, i also check the send connection in the edge server and is ok. so can anybody help pls
Failed to connect to the Edge Transport server ADAM instance with exception The supplied credential is invalid.. This could be caused by a failure to resolve the Edge Transport server name EXCH-EDGE.nddc.gov.ng in DNS, a failure trying to connect to port 50636 on EXCH-EDGE.nddc.gov.ng, network connectivity issues, an invalid certificate, or an expired subscription. Verify your network and server configuration.