Custom domain email guide · Verified July 30, 2026

How to send email from your custom domain in Gmail

Direct answer: in the current 2026 flow, add the branded address under Gmail’s “Send mail as,” use smtp.gmail.com with TLS port 587, authenticate with the personal Gmail address and its App Password, then confirm the code delivered through Brand My Inbox forwarding. Test the received headers before relying on it for business mail.

Open mailbox dashboard Read the setup steps

What this setup does

Personal Gmail receives the mail and currently sends with the branded From address

Brand My Inbox routes incoming messages for shai@em.domain.com to user@gmail.com. Gmail’s Send mail as setting then uses the personal Google account’s SMTP login and App Password to offer the branded address in the From menu.

Receive

Cloudflare routing → personal Gmail inbox

Send

smtp.gmail.com → branded From address

Verify

External test → inspect From, replies, and authentication

Security boundary

The App Password is entered only inside Google’s Gmail setup window. Brand My Inbox does not request, receive, or store it.

Visual setup map · about 3 minutes

From receiving mail to sending as your domain

Create an App Password

Enable 2-Step Verification in the personal Google account, then create a 16-character App Password.

Add the branded address

In Gmail, open Send mail as and add shai@em.domain.com or an address on the root domain.

Enter Google SMTP

Use smtp.gmail.com, TLS port 587, the personal Gmail username, and its App Password.

Confirm and test

Open Google’s verification email delivered through your forwarding route, confirm, and send an external test.

Create a Google App Password

In the personal Google account that owns user@gmail.com, turn on 2-Step Verification. Then open App Passwords, create a password named “Brand My Inbox” or “Custom domain,” and copy the 16-character value.

App Passwords may be unavailable for managed work or school accounts, Advanced Protection, or security-key-only configurations. Never enter the customer’s normal Google password into Brand My Inbox or the extension.

Open Google App Passwords

Add the custom address in Gmail

On a computer, open Gmail and select Settings → See all settings.
Open Accounts and Import (or Accounts).
Under Send mail as, select Add another email address.
Enter the sender name and the full address, such as shai@em.domain.com.
Leave Treat as an alias selected when this address represents the same person, then select Next Step.

Enter the outgoing SMTP settings

Authenticate with the personal Gmail account that created the App Password. The branded forwarding address is the visible From address, but it is not the SMTP username in this route.

Values for the personal Gmail SMTP route

These values apply to the current Gmail “Send mail as” setup described here. Replace the example username with the customer’s personal Gmail address.

SMTP server

smtp.gmail.com

Port

587

Username

user@gmail.com

Use the personal Gmail address—not the branded address.

Security

TLS

Password

16-character App Password

Use the App Password created in this same Google account, never the normal Google password.

Confirm ownership and activate sending

Google sends a verification message to the branded address. Because Brand My Inbox has already routed incoming mail to the personal Gmail inbox, the message should arrive there. Open it, follow the confirmation link or paste the code into the Gmail window.

Compose a new message, open the From field, select the branded address, and send to an unrelated external inbox. Then set both Make default and the reply-to address under Send mail as.

Problem solving

Gmail custom-domain troubleshooting

Authentication failed

For this personal Gmail route, use the complete user@gmail.com address and an App Password created by that same Gmail account. Do not use the branded address as the SMTP username.

Couldn't reach server

Recheck the SMTP hostname, choose TLS with port 587 or the provider's documented SSL setting, and confirm the provider permits authenticated SMTP.

Verification email missing

Confirm inbound forwarding works, then check Spam and search for send-as-noreply@google.com. Delete and re-add the address if the verification expired.

Gmail appears on behalf of

The SMTP service may not be authorized or aligned with your domain. Use a provider that signs your domain with DKIM and include that provider in your single SPF record.

Message lands in spam

Check SPF, DKIM, DMARC, sender reputation, and message content. DNS authentication improves trust but does not guarantee inbox placement.

App Password option missing

Turn on 2-Step Verification first. App Passwords may still be unavailable for organization-managed accounts, Advanced Protection, or security-key-only configurations.

Wrong From address on replies

Set both the default From address and the reply-to address. Gmail manages these as separate settings.

Extension session expired

Return to the Brand My Inbox mailbox dashboard and start Set up in Gmail again. Setup tokens are restricted to one address and expire after 20 minutes.

Direct answers

Frequently asked questions

Official sources

This guide is operational guidance, not a guarantee of inbox placement. Provider rules and Google account policies can change.