SMTP Error Code 501

The transaction failed permanently. The server will not try to send the message again. This is most commonly an issue with an incorrect/invalid email address.

Providers

GMX · GoDaddy · Orange · Outlook.com · QQ · Yahoo

GMX↑

501 Syntax error in parameters or arguments

Due to an incorrect configuration, email reception has been refused. Please contact your administrator who should correct the server configuration based on our recommendations and apply to us for the systems to be unblocked.

• https://postmaster.gmx.net/en/error-messages

GoDaddy↑

HELO/EHLO rejected. IB301

The server is rejecting the HELO/EHLO command. Try using a different HELO/EHLO string, and verify the one you are using isn't being abused.

Orange↑

501 5.1.0 Emetteur invalide. Invalid Sender. OFR004_405 [405]

This error suggests that Orange is seeing an issue with the Return-Path (SPF) of the message. Check the settings with your sending email provider to make sure your Return-Path is aligned with your sending domain.

Outlook.com↑

501 5.1.3 Invalid address [outlook.com]

QQ↑

501 Bad address syntax. http://service.exmail.qq.com/cgi-bin/help?subtype=1&&id=20022&&no=1000730

• http://service.exmail.qq.com/cgi-bin/help?subtype=1&&id=20022&&no=1000730

Yahoo↑

501 Syntax error in parameters or arguments

• https://postmaster.yahooinc.com/error-codes