Knowledgebase

If you are receiving the "5.7.1 Relaying not allowed" error message in your Outlook email client, your ISP is most likely blocking the ability for you to use a third-party smtp server, ie: mail.your-domain-here.com. To solve this error, you have to use your ISP's smtp server as your outgoing mail server in Outlook.

The following links are websites that has a list of known ISP that block the use of third-party smtp servers.

The list:

Earthlink Internet service: smtp.earthlink.net

MSN Internet service: smtp.email.msn.com

Verizon Internet service: outgoing.verizon.net

Qwest Internet service: pop.dnvr.qwest.net

OPTOnline Internet service: mail.optonline.net

SBC Internet service: smtp.sbcglobal.yahoo.com

SCB (Pacbell): mail.pacbell.net

SCB (SBC Global): smtp.sbcglobal.net

Comcast Internet service: smtp.comcast.net

At&T Broadband Internet service: mail.attbi.com

NetZero: smtp.netzero.com

RCN: smtp.rcn.com

DSLExtreame: smtp.dslextreme.com

MegaPath: mail.megapathdsl.net

Cable One: mail.cableone.net

XO Communication: mail.njd.xo.com

Cox Internet: Find your SMTP server based on your State: Cox Internet State-specific SMTP server names.

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