How to fix an SMTP Login Failure?

Thunderbird will not log in to SMTP to send emails; however, it will login to download emails. When a customer tries to send email, Thunderbird asks for the password, but the password used by customer (which is correct) Thunderbird says is not correct. Again, if the customer uses Em Client to send emails now, but it doesn’t work. Although he/she is using Windows 10 with the newest version of Thunderbird for windows.

Correct SMTP Login Failure Error in Thunderbird Email

If you cannot send messages, this page provides a series of steps you can use to check for common problems. If you have problems receiving messages, follow the simple steps:

Verify your SMTP outgoing email settings

• In the Thunderbird menu bar, click the Tools menu and select Account Settings, or click the Application menu button and select Options and Account Settings from the sub-menu, and select Outgoing Server (SMTP) from the bottom of the list in the left panel. Check that the settings are the same as documented on the mail settings article for your mail provider on support.mozilla.org (Gmail, Yahoo, Comcast, Hotmail, Sympatico) OR

• If there is no support.mozilla.org article with your specific mail provider’s mail settings, then look for an SMTP mail settings article on the mail provider’s site. This is usually in the support section of their website; searching for “mail settings” or “SMTP” will usually find it. Check that your Thunderbird settings match the documented settings.

Verify the correct SMTP Server is being used

• In the Thunderbird menu bar, click the Tools menu and select Account Settings, or click the Application menu button and select Options and Account Settings from the sub-menu, and select the account name. Verify that you are using the right SMTP server for the email address. Most of the time you cannot send messages from one account provider using another account provider’s service. For example, you cannot send a mail from “[email protected]” through Yahoo’s SMTP server.

Verify that your outgoing email is not being blocked

Verify that your outgoing email is not being blocked by your firewall, antivirus software or your Internet Service Provider:

• Try briefly turning both antivirus and firewall software off, sending a test email and turning them on and sending another test email.
• Many ISPs block outgoing email on port 25. You may have to switch to another port (e.g. 587 or 465). Contact your ISP’s support to see if they are blocking your outgoing email port.

Delete SMTP Password

Try deleting your SMTP password. However, don’t do this as a first step, especially if you cannot send messages after updating Thunderbird while you previously could. In such case, usually there is nothing wrong with a stored SMTP password in Thunderbird (see above).

Reset SMTP Password

Try changing your SMTP password. This is usually done via a ‘reset email password’ form on your ISP’s support website.

How to change SMTP password in Thunderbird? Normal procedure does not work

Password to my SMTP changed recently, and I can’t change it to Thunderbird due some bug.

Changing should work like this:

1. User send email
2. Thunderbird gets authentication error: Login to server my.smtp.server failed
3. Thunderbird prompts for new password: Enter New Password

The problem is that when I click Enter New Password, no password prompt appears, Thunderbird just tries to reconnect and that, of course, fails.

Is this a known bug? Is it fixed in later releases? Can I fix the problem manually by editing Thunderbird setting files?

Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.10) Gecko/20100528 Thunderbird/3.0.5

I am using Ubuntu 10.4 and the Thunderbird that comes with it.