I have a surface 3 tablet which comes with an e-mail application built-in. Composing messages generates a "sent from Mail for Windows 10" signature type of line in the e-mail. That's fine.
But outgoing mail just sits there in the outbox and never gets sent. This is for a gmail account which otherwise works fine. This client on this tablet receives e-mail fine -- it just can't send.
I suppose I could manually enter IMAP connection parameters, but that seems silly.
I'm fine with using the built-in client, which, presumably, is an outlook variant.