Messages send fine with attachments to most email servers. But we are running into an issue with some messages that do not send if there is a larger ~500KB attachment. I can send a large file to gmail for instance 5MB and it goes fine but if
I send to a recipient on AOL with an attachment of 500KB the connection to the server drops or times out.
I can then send a smaller attachment to the same recipient and message sends successfully.
Here is the SMTP Send Log:
014-01-27T18:18:25.359Z,Default,08D0E866E8D574F4,0,,64.12.138.161:25,*,,attempting to connect
2014-01-27T18:18:25.437Z,Default,08D0E866E8D574F4,1,205.155.233.2:19745,64.12.138.161:25,+,,
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,2,205.155.233.2:19745,64.12.138.161:25,<,220-mtain-mp03.r1000.mx.aol.com ESMTP Internet Inbound,
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,3,205.155.233.2:19745,64.12.138.161:25,<,220-AOL and its affiliated companies do not,
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,4,205.155.233.2:19745,64.12.138.161:25,<,220-authorize the use of its proprietary computers and computer,
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,5,205.155.233.2:19745,64.12.138.161:25,<,"220-networks to accept, transmit, or distribute unsolicited bulk",
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,6,205.155.233.2:19745,64.12.138.161:25,<,220-e-mail sent from the internet.,
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,7,205.155.233.2:19745,64.12.138.161:25,<,220-Effective immediately:,
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,8,205.155.233.2:19745,64.12.138.161:25,<,220-AOL may no longer accept connections from IP addresses,
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,9,205.155.233.2:19745,64.12.138.161:25,<,220 which no do not have reverse-DNS (PTR records) assigned.,
2014-01-27T18:18:25.750Z,Default,08D0E866E8D574F4,10,205.155.233.2:19745,64.12.138.161:25,>,EHLO gamma.sbcoe.k12.ca.us,
2014-01-27T18:18:25.828Z,Default,08D0E866E8D574F4,11,205.155.233.2:19745,64.12.138.161:25,<,250-mtain-mp03.r1000.mx.aol.com,
2014-01-27T18:18:25.828Z,Default,08D0E866E8D574F4,12,205.155.233.2:19745,64.12.138.161:25,<,250-STARTTLS,
2014-01-27T18:18:25.828Z,Default,08D0E866E8D574F4,13,205.155.233.2:19745,64.12.138.161:25,<,250 DSN,
2014-01-27T18:18:25.828Z,Default,08D0E866E8D574F4,14,205.155.233.2:19745,64.12.138.161:25,*,202772,sending message
2014-01-27T18:18:25.828Z,Default,08D0E866E8D574F4,15,205.155.233.2:19745,64.12.138.161:25,>,MAIL FROM:<sender email address>,
2014-01-27T18:18:26.093Z,Default,08D0E866E8D574F4,16,205.155.233.2:19745,64.12.138.161:25,<,250 2.1.0 Ok,
2014-01-27T18:18:26.093Z,Default,08D0E866E8D574F4,17,205.155.233.2:19745,64.12.138.161:25,>,RCPT TO:<recipient email address>,
2014-01-27T18:18:26.187Z,Default,08D0E866E8D574F4,18,205.155.233.2:19745,64.12.138.161:25,<,250 2.1.5 Ok,
2014-01-27T18:18:26.203Z,Default,08D0E866E8D574F4,19,205.155.233.2:19745,64.12.138.161:25,>,DATA,
2014-01-27T18:18:26.281Z,Default,08D0E866E8D574F4,20,205.155.233.2:19745,64.12.138.161:25,<,354 End data with <CR><LF>.<CR><LF>,
2014-01-27T18:18:58.656Z,Default,08D0E866E8D574F4,0,,64.12.88.131:25,*,,attempting to connect
2014-01-27T18:18:58.656Z,Default,08D0E866E8D574F4,22,205.155.233.2:19745,64.12.138.161:25,>,QUIT,
Thanks