Couldn't find anything for whitelisting.
As for my email, it's supposed to be a .com address email, I've found out since - I've become accustomed to putting in .co.nz (when I type in .com and/or .co.nz for accessing my email account, it sends me to the same email) so that might be a problem.
In basic terms, itch.io is trying to send emails to an email that yahoo itself redirects to its actual address (which ends with .com), but for whatever reason it isn't appearing there.