Hi Ree - Switching to a new subdomain can help improve deliverability temporarily, but it’s not a true reset button—especially if you continue sending to unclean or low-engagement lists.

A few things to know:

• Yes, using a new subdomain can give you a “clean slate” in terms of domain reputation (because mailbox providers see it as a separate identity).
• However, mailbox providers still monitor overall engagement and list hygiene. If the new domain immediately starts sending to spam traps or unengaged users, it’ll tank quickly too.
• Make sure your new subdomain is fully authenticated (SPF, DKIM, DMARC) before sending.
• Gradually warm up the new subdomain with smaller, engaged segments before scaling volume.

On changing the reply-to address:

Changing the reply-to address won’t break anything technically, but make sure it’s still monitored if you want to catch customer replies—or clearly state it’s a no-reply address.

In short:

Yes, it can help, but only if you pair it with better sending practices going forward (list cleaning, segmentation, sunset flows, etc.). You could also clean your list, tighten up segmentation, and rewarm your current domain as an option as well but you do need to improve hygiene and segmentation practices either way. 

You’re reaaaaaally not doing a good job of explaining why it’s a bad idea lol. You just said “If you fixed your list cleaning now and want quick results, then yeah, go ahead and switch!”.

So I’m gonna. And if I report back that everything turned out fine, I expect you to start giving *actual real advice* to your customers, because there’s a bunch of bad advice in your reply, Zac. There’s absolutely no problem in taking shortcuts like this, yet you seem to be forced to give bad advice.

“but it’s not a true reset button”. Yes it is, as nothing suggests otherwise. I’ll be back.

Hi ​@Ree_81 !

Zac is correct in what he’s saying - if you add a new subdomain this will not reset your deliverability score. Your deliverability score and sender reputation are attached to your root domain, not your sub domain. If you wanted to “reset”, you would need to create a new branded sending domain entirely and then go through warming for that domain. The warming process is outlined in further detail here: https://help.klaviyo.com/hc/en-us/articles/360025945671#h_01HFA4HFQTPA3JKWA2WY1SEJF8 .

Essentially, if you just changed your subdomain, inbox providers can connect the dots back to your root domain reputation and will go based off of that. 

Here is our guide for repairing your sender reputation if you decide to stick with the same domain: How to repair your sender reputation

I hope this helps clarify!