Question

IP blacklisted / on spam list? How to notify Customer.io deliverability team?


Today I got a bounce due to one of CIO’s broadcast sending IP’s being blacklisted. I thought the deliverability team managing the shared IP’s would want to know, but am not sure how to inform them. Also are there any workarounds I can do on my end? Thanks!

Here was the error:
sip.invaluement.mimecast.org Blocked by ivmSIP and/or ivmSIP/24 - see https://www.invaluement.com/lookup/?item=198.244.52.4. - https://community.mimecast.com/docs/DOC-1369#550 [rl4gU84TO7ml-DrNJ6SiLQ.usb12]


3 replies

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Hi @mtwsf - thank you so much for reaching out here!

Jumping right into your question, our deliverability team has monitoring in place to check for blocklistings, which allows them to action them accordingly.

That being said, the blocklists that you mentioned are fairly niche, and are not ones used by any major inbox provider. In today’s email landscape, deliverability largely relies more upon the reputation of your domain, more than the IP address(es) you’re sending from. Are you currently seeing any any bounces as a result of these listings?

I hope that this helps to provide some clarity to you here. If you are seeing bounce issues due to these listings, please feel free to reply to this post or send a DM to include more details. Thank you kindly for your time!

Hi @aaron thanks for the note. Unfortunately we have had a 3% bounce rate out of the ~100 emails we sent attributed specifically to that blocklist so far. Also for what it’s worth, a lot of our target audience are in older nonprofit institutions that tend to use either more niche or less current technology than the average, so that may be why their email filters are marking it with that ivmSIP listing.

If we notice that, is it ok to go to the invaluement website and ask for the IP to be delisted or is that something you guys have to do?

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Thank you so much for your reply @mtwsf - I let our deliverability team know about the listing just in case it is something that they are able to action. For transparency, some blocklists do not allow delisting, but rather they have to expire (i.e. Backscatterer). In this case, given what you mentioned regarding the bounce rate, what we identified as the more immediate solution was to go ahead and rotate the IP out for you. 

If the bounces you saw from your sending earlier were soft bounces, they should have been automatically retried for delivery. If they were hard bounces (due to the IP listing), you are welcome to retry those manually now that the existing IP has rotated off and a new IP rotated on. You can do that from either the Sent page of your campaign/broadcast or directly in the Delivery Logs, where you can click to expand a delivery row and click Retry. I’d recommend trying a small handful first before retrying in bulk, just to get a pulse-check on delivery those recipients going forward. Let us know if you need anything else!

 

Best,

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