Walmart/Asda appear to be using Proofpoint from a cursory glance. What makes you think they are using Trend Micro?
The rejection message specified the RBL in question, one that our monitoring service didn't include, which is at
https://www.ers.trendmicro.com/reputations.
You should be looking at AAISP for something like that. My experience with Zen as a company is that they are not very technical...
We were with AAISP for many years but lost all connectivity one morning for over an hour, despite being synced with the DSLAM at the local exchange, until we rang them from a mobile. It turned out that they had an administrative query so they had turned off our service
(including the VOIP telephone service they were providing us with),
then sent us an e-mail about it! For reasons that 99.9% will understand immediately, we didn't get the e-mail until they restored service.
Ironically, the "business continuity service" they offer, which we had considered at length, would also have been turned off with the DSL service - we changed to Zen because we need trust in our service provider and we have none in AAISP for obvious reasons.
Edit: AAISP's "administrative query" was not in any way related to an unpaid invoice or any financial issue. It was a completely unexpected, unnecessary and drastic action in the circumstances.
If you are running your own system you need to be proactively monitoring deliverability and blocklists etc.
We do, but only the bigger ones, which didn't include the Trend Micro DUL RBL.
Edited by deleted (Thu 21-Jul-22 13:38:43)
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