I have just created a Yahoo e-mail account and sent an e-mail using a web browser to my "normal" e-mail address. I use Outlook to receive e-mails on my "normal" e-mail address.
I don't receive the plain text test message that was sent from my new Yahoo e-mail address. If I send an e-mail from my yahoo e-mail account to my yahoo e-mail account then that is received by yahoo mail.
In bot cases the Yahoo mail web application give a confirmatory message "Mail Sent".
I have no issues receiving any other e-mails on Outlook mail. and in both cases the Yahoo mail outbox lists the e-mail messages in the Sent items.
Can anyone account for this ?