ENH: Connection failures should not be misleading and say "please run connect() first"

[metaperl]

Is your feature request related to a problem? Please describe.
When the connection fails, one receives the misleading exception: "please run connect() first" which is coming from red-mail calling smtplib.

Describe the solution you'd like
Provide an accurate and descriptive feedback that connection failed.

We ran the simplest red-mail script possible:

from redmail import EmailSender
from smtplib import SMTP

email = EmailSender(
    host="false-host",
    port=25
)

and got a totally misleading error message: "please run connect() first" instead of being told the connection failed.

Once we switched host to localhost the script ran fine.

[metaperl]

A little more detail on this: this cryptic error message only occurs in our work environment where there are proxies that block access to certain domains.

At home, I get a descriptive error message for the following program:

from redmail import EmailSender

email = EmailSender(
    host='fakedomain.livingcosmos.org',
    port=25
)


def main():
    email.send(
        subject='email subject',
        sender="me@example.com",
        receivers=['you@example.com'],
        text="Hi, this is an email."
    )


# Press the green button in the gutter to run the script.
if __name__ == '__main__':
    main()