We send less than 100K emails a month so we've had to use the Shared IP option in Salesforce. In the last month, we've had it happen twice where we saw huge spikes of Hard Blocked emails upwards of 25%. We've had to contact Salesforce support to have them investigate and report back to us that since we use a shared IP we don't have control over our reputation and that our reputation is only as good as the weakest senders on the shared IP. As a result of others neglectful practice, everyone else on the IP can be negatively affected. The first time they sorted it out for us and our deliverability improved. 3 weeks later this is happening again and support is giving me little help on how to rectify it.
Has this happened to anyone else? Is there anything you would recommend doing to help mitigate this happening in the future? This impacts our revenue and I'm hoping we don't have problems like this all the time.
Have you put your email list through an email verification tool such as BriteVerify? Hard Bounces tend to be invalid email addresses and not because of reputation. If it's due to reputation from using a Shared IP, it would be a Block Bounce. Query your _bounce data view to get the reasons why they were bounced.
https://help.salesforce.com/s/articleView?id=000387252&type=1
