Send Mail AS Error - SMTP Server

[gloq123]

In the Send mail as: options, when I am adding my additional account it continues to give an authentication error(wrong username/password). Is the "Username different than my email address? I have confirmed my password is correct, I've not recently changed that....I'm just adding my other google account. Thank you

[StephenHind]

@gloq123 if your other account users 2-step verification then you need to make an App Password for your other account and use that app password instead of your normal password - see: Sign in with App Passwords