Trace: Tracing message with Message ID [898167C01D8241B5A357583380905F77.MAI] from the SMTP Inbound Queue Result: [898167C01D8241B5A357583380905F77.MAI] was not routed from the SMTP inbound message queue by the local MTA Service. SMTP Debug log matches: Virus filter log matches: Error with reading l...

I have some customers that can not send to some addresses. Trace results show a 500 5.5.2 unrecognized command. See below. can anyone tell me the exact error message? the only thing I find while doing some searches is that the recipient box is full or something of that nature. I have ruled that out....