Shared Sending IP doubled sending volume, decreasing reputation score

  • 16 April 2024
  • 3 replies


I’ve been noticing that we’ve had an increase in bounces on comcast and yahoo emails over the past 2 months. A recent campaign bounced back over 300 comcast emails so I dug deeper. The sending IP can be tied back to other issues I’ve seen:


I used Comcast postmaster tools which drove me to Sender Score. Compared to the other IPs our domain sending has been attributed to, this one had a score of 6 and appears that something happened in April:

Send volume more than doubled for this IP. Is there a spam attack? Could Klaviyo have moved a large amount of brands to this one IP on accident or something?


Anyone else having issues as well?

3 replies

Userlevel 5
Badge +20

Hi @heckdevo,

I noticed the same thing in my account; our last campaing had more than 1100 bounces, with 900+ being from comast. I contacted Klaviyo support, and they manualy changed the set of shared IPs for my account. That being said, our next campaign isn’t scheduled until tomorow, so I don’t know for sure if the issue is fixed or not. Good luck!


@JessFosnough They just moved us to a new set of shared IPs thankfully! But definitely a reminder that we all have to put on our detective hats sometimes and make sure to report and push on anything that looks wrong.

Userlevel 5
Badge +25

Hey friends! Confirming there was a temporary spam block on one of the shared IPs. It’s since been cleared and should be all set now :)