Why can't I send an email to myself from myself?
Sending a message from one email address, to the same email address is a big red flag for spam filters.
It’s important that we take every step we can to ensure that the deliverability rate for your emails to your bookers is consistent and reliable so we have taken the decision to prevent sending a notification to the same email address you're sending from.
If you can, you should send it from a different email address on your domain. If that isn’t possible we will send it from our default address: firstname.lastname@example.org.