There is no screenshot.

Wouldn't load last time. Here it is.

So, what does "cannot send email" mean? What happens? What doesn't happen? Any error messages to share with us?

The screenshot show\s what happens in descending order. First I get the "Login to server... failed" so I hit retry - nothing, then I hit "Enter New Password" whereupon I enter the current password. It still will not work so I then hit cancel and get the last message "Sending of the message failed..."

I'm using these settings and everything is ok. See image below.

Server name: smtp.gmail.com Port: 465 User Name: full gmail email address Authentication method: OAuth2 Connection Security: SSL/TLS

When using OAuth2, gmail will ask you to verify it is you the first time. Since using OAuth2 I've not been pestered to keep verifying.