SMTP to Gmail Authenticated Relay not working email stuck in queue

Question

I am following this document

http://kb.eclipseinc.com/kb/how-to-configure-iis-smtp-server-to-forward-emails-using-email-account/

and in places where it was talking about ports etc i used the information

Gmail SMTP server settings

1. Gmail SMTP server name: smtp.gmail.com

2. Gmail SMTP username: your Gmail address

3. Gmail SMTP password: your password

4. Gmail SMTP port: 465

I also enabled TLS

but mails sent just get stuck in queue

My Settings

Answer 1

Mails sent just get stuck in queue

You need to use port 587 with TLS.

• Gmail SMTP port (TLS): 587
• Gmail SMTP port (SSL): 465

Source What Are the Gmail SMTP Settings?

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I'm getting an error message that my app is not secure

Someone just tried to sign in to your Google Account [email protected] from an app that doesn't meet modern security standards.

You need to change a setting on your Gmail account.

• Login to Gmail

• Go to "My account"

• Select "Sign-in & security"

• Scroll to the bottom of the page

• Set "Allow less secure apps" to "ON"

Try to send your emails again.

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Allowing less secure apps to access your account

Google may block sign-in attempts from some apps or devices that do not use modern security standards. Since these apps and devices are easier to break into, blocking them helps keep your account safe.

Some examples of apps that do not support the latest security standards include:

• The Mail app on your iPhone or iPad with iOS 6 or below
• The Mail app on your Windows phone preceding the 8.1 release
• Some Desktop mail clients like Microsoft Outlook and Mozilla Thunderbird

Change account access for less secure apps

To help keep Google Apps users' accounts secure, we may block less secure apps from accessing Google Apps accounts. As a Google Apps user, you will see a "Password incorrect" error when trying to sign in. If this is the case, you have two options:

• Option 1: Upgrade to a more secure app that uses the most up to date security measures. All Google products, like Gmail, use the latest security measures.

• Option 2: Change your settings to allow less secure apps to access your account. We don't recommend this option because it might make it easier for someone to break into your account. If you want to allow access anyway, follow these steps:

  1. Go to the "Less secure apps" section in My Account.
  2. Next to "Access for less secure apps," select Turn on. (Note to Google Apps users: This setting is hidden if your administrator has locked less secure app account access.)

Source Allowing less secure apps to access your account

Answer 2

I may little late, experienced a similar issue, this was after May 30, 2022.

This feature is no longer supported as of May 30th, 2022. See Less secure apps & your Google Account.

Use an App Password

An App password is a 16-digit passcode that gives a non-Google app or device permission to access your Google Account. Learn more about how to sign in using App Passwords.