Exchange Server rejects huge e-mail messages

Symptoms:

Messages bigger than 10 MB are not transferred by Narawen Inox POP3 Connector. They are downloaded from POP3 mailbox and retried to be sent without effect.

Additionally in Application event log InoxSvc records following message:

Report for message 1 of 1 from xxx@xxx

Delivery report:
Status: Not completed
xxx@xxx:
Not delivered. Connection to smtp://exchange-server:25 reported protocol error. 552 5.3.4 Message size exceeds fixed maximum message size.

Message details:

The hint is “fixed maximum message size”. Usually the limit is set in recipient policy. In that case increasing limit at recipient policy will not help. To adjust “fixed maximum message size” proceed with following steps:

1. Exchange Server Management Console
2. Organization Configuration
3. Hub Transport
4. Locate the appropriate Receive Connector
5. Adjust the value of the Maximum Message Size (KB)