QQ is an instant messaging service that includes email, social groups and games, and online chat products, headquartered in China as part of Tencent. Email delivery can be unpredicatable for non-Chinese businesses or when sending through mailservers outside of China. For the most insight, register your Return-Path domain with QQ's Postmaster site to directly monitor delivery and respond to any spam complaints.
Codes
- 501↑
501 Bad address syntax. http://service.exmail.qq.com/cgi-bin/help?subtype=1&&id=20022&&no=1000730
- 550↑
550 Mail is rejected by recipients
You are on this recipient's personal blacklist or your message has been rejected because of a filter they've created.
550 Mailbox unavailable or access denied
The recipient you're trying to send to is receiving a large number of emails in a short period of time. To avoid malicious attacks, sending to this recipient is temporarily prohibited.
550 Mailbox not found.
This recipient does not exist.
550 Mail content denied.
The content of the email was suspected of being sent in large numbers and was reported by a lot of users as spam.
550 Sender frequency limited.
The sender 's sending frequency exceeded the limit. The amount of time that further mail is prohibited from being delivered depends on the limit exceeded. (for example, sender, hourly, daily). These limits are not disclosed.
550 Suspected spam sender.
Suspected of spam/a large amount of spam was sent from the domain name or mail operator.
550 DMARC check failed
The email failed DMARC and you have a reject policy. Make sure your email is authenticated and aligned with SPF and/or DKIM. Contact your email provider for more details on how to configure them.