I have pretty the same issue as described here, but with the difference, that the solution there does not work for me:
I'm trying to send an administration mail to a @hotmail.com and a @mydomain.com address. The mydomain mail account is infact a Gmail account.
The admin mail arrives fine at the Hotmail-account, but there is no trace of it in the Gmail-account (no, it is not in the spam folder).
I tried all kinds of combinations with the "E-Mail from address" and the "Use this as the "From" email address for Administrative recipients of this form?" option in the form itself. Also set both to the WP-Admin mail address with no result.
Any more suggestions..? Would be really appreciated...
Thanks in advance