Some of our emails are getting blocked by Spamhaus.
Here's what the bounced emails look like:
The following message to <email@example.com> was undeliverable.
The reason for the problem:
5.1.0 - Unknown address error 550-'5.7.1 Service unavailable; Client host [22.214.171.124] blocked using Spamhaus; To request removal from this list see http://www.spamhaus.org/lookup.lasso'
Reporting-MTA: dns; mta24-d1.ip2.cbr1.mail-filtering.com.au
Status: 5.0.0 (permanent failure)
Remote-MTA: dns; [126.96.36.199]
Diagnostic-Code: smtp; 5.1.0 - Unknown address error 550-'5.7.1 Service unavailable; Client host [188.8.131.52] blocked using Spamhaus; To request removal from this list see http://www.spamhaus.org/lookup.lasso' (delivery attempts: 0)
I have opened http://www.spamhaus.org/lookup.lasso
Entering my Client Host IP (184.108.40.206) into IP Address Lookup Tool returns:
220.127.116.11 is not listed in the SBL
18.104.22.168 is not listed in the PBL
22.214.171.124 is not listed in the XBL
Entering my domain, mincad.com.au, in to the Domain Lookup Tool returns:
mincad.com.au is not listed in the DBL
So we are not listed on any of the Spamhaus lists - but our emails to 3 customers are being blocked?
Do you have both an external IP and also an email server IP? Check both if you do.