I have a Google Workspace account with a single email address: [email protected]. I enabled POP access in the Workspace account, and also configured an "alternate email" (alias): [email protected].

I also have a personal (free) Gmail account: [email protected]

In the personal account, I successfully set up both "Send mail as" and "Check mail from other accounts" for the Workspace account [email protected]. This all works well.

However, I cannot figure out how to "send mail as" my Workspace alias [email protected] from my [email protected] account. When I try to set it up I always get this error: "Authentication failed. Please check your username/password" I am using the app password as required.

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2 Answers 2



Regardless of whether using a Google Account's primary email address for a "Send As" alias, or an email alias of that account, you must always use the account's username to authenticate via SMTP, and the account's username follows the account's primary email address.


The instructions that follow are to configure one Gmail account ("AccountToConfigure") to "Send mail as" a Gmail address associated with a separate Google account ("OtherAccount") that you control.

The wrinkle, in this case, is that the messages are being sent on behalf of one of OtherAccount's email aliases, [email protected], rather than its primary email address.

Regardless of this distinction, the setup is almost identical but this distinction often trips users up because they don't specify the correct username, and the nuance of the use case is often overlooked by helpers when those same users seek support.

Background Info for OtherAccount

Primary Email: [email protected]
Username:      [email protected]  // is the primary email
Password:      Password1!
Email Aliases: [email protected]
               [email protected]
               [email protected]     // alias used in this example


Steps to send mail as [email protected], an email alias of OtherAccount.

  1. Get an app password for OtherAccount
  2. Configure "Send mail as" for AccountToConfigure

Step 1: Get an app password

This step is common regardless of whether you want to "Send mail as" OtherAccount's primary address, or one of its aliases.

You can skip this step if you already have an app password, however, for security reasons, I suggest creating a separate app password each time you need one using an informative label. This will allow you to remove old ones that may no longer be needed without the risk of impacting multiple places where they may be reused.

Step 1 is done in OtherAccount. If you are not already logged in to OtherAccount, ensure you are logged out of all other accounts and authenticate with OtherAccount's credentials when prompted by Google.

  1. Navigate to Google's App Passwords page: myaccount.google.com/apppasswords

    Alternatively, while logged in to your Google Account, select Security, then 2-Step Verification (under "How you sign in to Google"), and then App passwords (at the bottom of the page).
    See Google Help > Sign in with app passwords

  2. Specify an informative app name such as: "send mail as [email protected]" and then click Create

  3. Copy the generated app password, mhaq pdiy mnfc hhnc in this example, then click Done

Step 2: Configure "Send mail as"

This portion is done while logged in to AccountToConfigure. You can first log in to that account or start logged out of any account and authenticate with AccountToConfigure when prompted by Google.

  1. Access the Gmail settings for "Accounts and import" at
    1. Click Add another email address located at the bottom of the "Send mail as" section.

    2. In the "Add another email address you own" dialog click Next step » after specifying the following values:

      Name:          John Doe             // customize as you prefer
      Email address: [email protected]   // alias in "this" case
      Alias:         ☑ Treat as an alias
    3. In the SMTP server settings, click Add Account » after specifying the following values:

      SMTP Server: smtp.gmail.com
      Username:    [email protected]  // *always* the primary email address
      Password:    mhaqpdiymnfchhnc        // the app password without spaces
      Port:        587
      Connection:  ☑ Secured connection using TLS

At first time when asked for mail address then put "[email protected]" and second time when again asked for mail address put "[email protected]". It worked for me. I used 16 letter App password. Both POP and SMTP disabled so that doesn't matter.

  • Thanks. Now that I have figured out to do it (based on the other answer), I can confirm that this answered the question, but it wasn't very clear. Specifically, it wasn't clear what 'at first time when asked for mail address' and 'second time' was referring to. Just wanted to give that feedback! Thanks for the answer. Jan 2 at 5:05

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