I have tried a few times to create accounts but everything produces:
"Tried to send you an e-mail but failed".

One had a 4 letter high-level-domain (.Info)
Another had a 3 level high-level-domain (.net)

I check each account on my e-mail system and all can send and receive messages.

What can be happening?
I tried to check the logs but found nothing pertaining to attempts for new accounts.

Thoughts?

New installation of 2.7 on my own server. It may be that out-going e-mail has not been set up.  Where do I look?

Here is what is displayed:

error/auth email/auth emailnoemail