I can send normal emails to him. I'm pretty sure that it is his firewall. I just want everything covered before I start putting the issue on another IT department. Russell W. Leighton, Jr. American Association for Respiratory Care IT Coordinator 9425 N. MacArthur Blvd, Suite 100 Irving, TX 75063 Direct: 972-406-4671 Fax: 972-484-2720 -----Original Message----- From: LISTSERV site administrators' forum [mailto:[log in to unmask]] On Behalf Of [log in to unmask] Sent: Thursday, March 11, 2010 1:09 PM To: [log in to unmask] Subject: Re: Invalid sender address Russell Leighton <[log in to unmask]> wrote on 03/11/2010 12:54:19 PM: > I am getting this error for just this user on one of my lists. When he > tries to manually login to my listserv site he gets this error: > "SonicWALL - Blocked by Application Firewall". I think his firewall is > blocking my listserv emails because he is the only account on that list > that gets an error message back to me. Someone's SonicWall firewall, possibly at the user's site, is blocking the connection to your listserv server. I would be that it is because the URL contains ".EXE" and it thinks it may be a link to an executable malware and bblocks it. > This is what I receive from my listserv. > > Your message did not reach some or all of the intended recipients. > > Subject: Re: Modified Early Warning System > Sent: 3/11/2010 10:16 AM > > The following recipient(s) cannot be reached: > > [log in to unmask] on 3/11/2010 11:49 AM > There was a SMTP communication problem with the recipient's > email server. Please contact your system administrator. > <mail.AARC.ORG #5.5.0 smtp;550 Invalid sender address > (#5.7.1)> Is this the same user?? The web access issue is probably separate from an invalid address issue. Can you send emails directly to this user? > I am just trying to cover all my bases before I tell his IT department > to look at their side. Has anyone had this error that ended up being > their fault. Lots of luck on that one! Confidentiality Notice: This electronic message and any attachments may contain confidential or privileged information, and is intended only for the individual or entity identified above as the addressee. If you are not the addressee (or the employee or agent responsible to deliver it to the addressee), or if this message has been addressed to you in error, you are hereby notified that you may not copy, forward, disclose or use any part of this message or any attachments. Please notify the sender immediately by return e-mail or telephone and delete this message from your system.