WordPress Speed Up Service | WordPress Website Maintenance Packages Reply To: Registration emails don’t send, all others do., by HonestRepairAdmin Thanks for the reply. I’ve got an update to my problem! I believe that it was a plugin conflict. Perhaps an old SMTP plugin messed something up, or perhaps iThemes Security is blocking emails to throwaway email addresses. Whatever it is, I fixed it by swinging a broken bottle around. I have also recently installed the “SB Welcome Email” plugin and all seems well. Tested and confirmed. If anyone else has problems I’d suggest disabling plugins one-by-one and trying to register a test user. Also try legitimate email accounts as well as throwaway accounts (like spambog or discardmail). Reply To: Registration emails don’t send, all others do.