| Event Id | 1224 |
| Source | MSExchangeMTA |
| Description | Invalid functional units were proposed at index <index name> during session-level negotiation. [<value> <value> <value> <value>] () |
| Event Information | The OSI stack determined that the remote system's session layer is proposing illegal values during a connection attempt. Use Network Monitor to capture Network Traces, then view these traces from Network Monitor for any network issue. Notify the remote system administrator that the remote message transfer agent (MTA) is malfunctioning. |
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