Many ISPs (internet service providers) block outgoing emails from anyone who is not a subscriber. This is an anti-spam feature; the ISP knows who you are when you send emails.
If the ISP you are connecting through blocks emails, outgoing emails would not go through, and instead you would get (in Thunderbird) an error message: “An error occurred sending mail: The mail server sent an incorrect greeting: cannot connect to SMTP server [the IP address of the server], connect error 10060.”
Normally, if you have house mates, any house mates need to put Your account information in their email program to send out emails. You would either have to type in your account information, or give it to them. They would be essentially sending emails as you, as far as your ISP is concerned.
Or, if you are a consultant, to send emails you would need to get your client’s ISP account information to send emails, definitely not professional.
Or you would have to use web mail.
If you (or your house mates) have web site hosting, then use the security of the web hosting account, instead of the security of the ISP account.
This is Very useful for people who have a notebook computer and connect from different locations, as you can send emails even if an ISP only permits their subscribers to send emails via SMTP port 25, without re-configuring your email settings.
I have web hosting through LunarPages.com, and use Thunderbird for my emails. If you have a different host or different email program, adjust accordingly.
The configuration for Thunderbird and LunarPages is:
In Tools, Account Settings, scroll down past “Local Folders” (see image 1)
Click on Outgoing Server (SMTP): (image 2)
Select the account you want, click Edit (or click Add)
Settings like this work: (image 3)
Description is for your use, put what you like there.
Server name: use the server for your web hosting account
If your ISP blocks smtp port 25, try port 587 or port 26.
User Name: your web hosting account name
Use secure connection: TLS, if available (uses your web hosting sign in, instead of your ISP sign in, to validate who you are independent of the ISP you are connecting through.