Email deliverability problems with Apple domains?

MatthewM Chicago, ILCommunity Member, Qualtrics Brand Admin Superuser ✭✭✭✭
edited June 22 in XM Directory

Has anyone noticed a recent uptick in bounced emails from recipients with Apple domains (,, and Over the last month or so, they've gone from being no more numerous than any other domain in my hard bounces to making up at least 90% of them. The diagnostic messages all say "smtp; 550 5.1.1 <[email address]>: user lookup success but no user record found --[code]". Just curious to know what is happening, and if Qualtrics is aware.