Customer running an Exchange Server organization and Active Directory domain on the Windows Server 2012 R2 updated environment which contain 5 Exchange Servers. Two servers are used for Exchange Mailbox, Two servers are used for Exchange Client Access and One server is used for Exchange Edge. All these servers are running Exchange CU10. We have purchased Office 365 E3 plan subscription and deployed hybrid configuration of Exchange Online. We are also using Web Application Proxy to published the Exchange virtual directories. Our MX record is pointed on the Office 365 EOP and we have configured a relay option between Office 365 Exchange Online and onprem Exchange (on the Exchange Edge Server) with a SMTP domain of “mx.domain.com”. We have also published all the DNS records to a public DNS for the accessibility of Exchange virtual directories from an External side..
Currently in our organization a Mail flow issue is occurred between Office 365 and Exchange Edge (Hybrid environment). We have configured a relay setting between Office 365 Exchange Online and Exchange on-prem Environment (on the Exchange Edge Server). We are unable to send or receive emails having attachments larger than “05” MB from everywhere. But in other hand we are able to receive plain text emails from any domain. Our Office 365 users are able to send and receive emails with or without attachments but on premise users are unable to receive or send. These below error I received on the Office 365 Exchange Online message trace.
Errors:
- [{LED=400 4.0.0 Message delivery delayed in active queue}{MSG=};{FQDN=mx.domain.com};{IP=202.141.250.131};{LRT=10/5/2016 9:03:44 AM}]. OutboundProxyTargetIP: 202.141.250.131. OutboundProxyTargetHostName: mx.domain.com
- [{LED=450 4.4.318 Connection was closed abruptly (SuspiciousRemoteServerError){MSG=};{FQDN=mx.domain.com};{IP=202.141.250.131};{LRT=10/5/2016 9:03:44 AM}]. OutboundProxyTargetIP: 202.141.250.131. OutboundProxyTargetHostName: mx.domain.com
- [{LED=451 4.7.0 Timeout waiting for client input}{MSG=};{FQDN=mx.domain.com};{IP=202.141.250.131};{LRT=10/5/2016 9:03:44 AM}]. OutboundProxyTargetIP: 202.141.250.131. OutboundProxyTargetHostName: mx.domain.com
- [{LED=400 4.0.0 Message delivery delayed in active queue};{MSG=};{FQDN=mx.domain.com};{IP=202.141.250.131};{LRT=10/5/2016 9:03:44 AM}]. OutboundProxyTargetIP: 202.141.250.131. OutboundProxyTargetHostName: mx.domain.com
- [{LED=450 4.4.318 Connection was closed abruptly (SuspiciousRemoteServerError)}{MSG=};{FQDN=mx.domain.com};{IP=202.141.250.131};{LRT=10/5/2016 9:03:44 AM}]. OutboundProxyTargetIP: 202.141.250.131. OutboundProxyTargetHostName: mx.domain.com
MCT & Infrastructure Consultant