Cause : The recipient's mail server is temporary unavailable

Common error message
1. Reason: 4.1.0 - Unknown address error ('451', ['Requested mail action not taken: mailbox unavailable'])
2. Reason: 4.3.2 - Not accepting messages at this time ('421', ['Too many bad recipients'])
3. Reason: 4.1.0 - Unknown address error ('451', ['4.3.2 Please try again later'])
4. Reason: 4.1.0 - Unknown address error ('450', ['4.7.1 : Recipient address rejected: Service is unavailable'])
Resolution
Due to the recipient's mail server is temporary unavailable, please contact recipients IT support for this issue, or wait for the recovery of their mail service and we'll keep resending this email.
Cause : hiBox's IP is listed on limited sender list of receivers mail server

Common error message
1. Reason: 4.1.0 - Unknown address error ('450', [': Recipient asked sender to resend. Greylisted for xxx seconds'])
2. Reason: 4.1.0 - Unknown address error ('451', ['4.7.1 Greylisting in action, please come back in 00:05:00'])
3. Reason: 4.1.0 - Unknown address error ('450', [': Recipient address rejected: Greylisted, see http://xxx.xxx.xx'])
4. Reason: 4.1.0 - Unknown address error ('451', ['4.7.1 Greylisting in action, please come back later'])
Resolution
1. Please wait for system to resend email.
2.Or contact recipient's IT support to add hiBox IP (210.71.187.1~254) to white list, and dial hiBox-toll-free 0800-080-365.
Cause : Recipients mailbox is over quota

Common error message
1. Reason: 4.1.0 - Unknown address error ('552', ['mail size or count over quota.'])
2. Reason: 4.1.0 - Unknown address error ('552', ['Requested mailbox exceeds quota.'])
Resolution
Due to the recipients mailbox is over quota, please contact the recipient to clean up mailboxs space.
Cause : hiBox's IP is listed on bad sender list

Common error message
Reason: 4.1.0 - Unknown address error ('450', ['4.7.1 : Recipient address rejected: Policy rejection: Abuse. Sending server blacklisted.'])
Resolution
Please contact recipient's IT support to add hiBox IP (210.71.187.1~254) to white list, and dial hiBox-toll-free 0800-080-365.
Cause : Your email is treated as spam mail by the recipients mail server

Common error message
Reason: 4.3.0 - Other mail system problem ('451', ['DT:SPM mx3, lwmowKCbCwFBXdZLEER9AA--.1892S2, please try again 1272339778 http://mail.163.com/help/help_spam_16.htm?ip=210.71.187.217&hostid=mx3&time=1272339778'])
Resolution
Due to your email is treated as spam mail by the recipients mail server, please modify your mail subject or content for avoiding this problem.
Cause : Your email is temporary deferred by the policy of recipients mail server

Common error message
Reason: 4.1.0 - Unknown address error ('450', ['4.7.1 : Recipient address rejected: Policy Rejection- Please try later.'])
Resolution
Your email is temporary deferred by the policy of recipients mail server. HiBox is trying to re-send your email.