I made a custom e-mail address on Cloudflare, and have tried adding it to Gmail as a sender address following this tutorial, but I get stuck on the SMTP Server, Username, Password section when I get the following authentication error:

Authentication failed. Please check your username/password. Server returned error: "535-5.7.8 Username and Password not accepted. Learn more at 535 5.7.8 https://support.google.com/mail/?p=BadCredentials d18-20020a170906305200b00730799724c3sm240511ejd.149 - gsmtp , code: 535"

I have tried with Port 465 and SSL and Port 587 and TLS.

CodePudding user response：

This answer solved it.

To generate an App Password you can do this:

1. Go to your Google Account.

2. Select Security.

3. Under "Signing in to Google," select App Passwords. You may need to sign in. If you don’t have this option, it might be because:

   a. 2-Step Verification is not set up for your account.

   b. 2-Step Verification is only set up for security keys.

   c. Your account is through work, school, or other organization.

   d. You turned on Advanced Protection.

4. At the bottom, choose Select app and choose the app you using and then Select device and choose the device you’re using and then Generate.

The steps were copied from here.