Our team executed a remailer campaign on 2/18 to site registrants from 9-12 months ago. Immediately upon executing the campaign, we began to experience massive declines in open rates for 4/10 of our campaigns live (everything is triggered on site registration) - going from 55%+ open rates to a mere 2-3%.
Has anyone had any experience with resolving this? Any new campaign we launch goes right into Gmail spam - no older trigger campaigns and no other email clients are impacted.
how many contacts were in the 2/18 send?
If your data is 9-12 months old and haven't been sent an email in that long, there'd be a good chance your bounce rate for a single send was too high which damaged your sender score.
There are many other factors though, how old is your sending domain? are you on the shared marketo ip ranges? honeypots in your lists, content in your emails
The send was to 500k users who registered 9 months ago. Would sender score solely impact gmail? All other email clients are unaffected.
Our sending domain is 1.5yrs old & we are on a shared IP. If this was across the board, I'd assume those are the cause but again, this is only impacting 4/10 campaigns and specific to just gmail.
Not certain, but it's likely you hit a gmail spam trap. A Guide to Spam Traps + How to Avoid Them * note the inactivity period, best to do clean ups every 6 months.
Check info around the web for remedy actions, Bulk Senders Guidelines - Gmail Help