We have a ~98.5% delivery rate with iCloud.com, me.com, and mac.com, but see ~50% missing in inbox placement testing with Everest, even with 100% of the messages in the returning 250s. The primary domains, Gmail, Yahoo, Hotmail, don't seem to have this issue and our delivery rate is approximately represented in inbox placement testing to within a couple percent.
Is anyone else experiencing an isolated mismatch between inbox placement testing general sending statistics?
Quick update here so everyone is in the know. The 250 delivery log will show you what percent of your email was delivered to the mailbox providers, but it doesn't show us where the email landed on the subscribers end. We're still investigating this with SeattlePC, by looking for any block bounce messages for this specific domain (icloud.com, etc.)