Connect Zoho Mail
Connect a Zoho mailbox with an app-specific password and the correct regional SMTP/IMAP hosts.
Zoho connects over SMTP/IMAP with an app-specific password. The setup is straightforward, but one detail trips up more people than everything else combined: Zoho's mail servers are regional, and using the wrong region's hostname fails with an authentication error that looks like a wrong password.
If you get "535 Authentication Failed" with credentials you know are correct, you are almost certainly pointing at the wrong regional host. A Zoho account registered on zoho.in will not authenticate against smtppro.zoho.com — it needs smtppro.zoho.in. Match the host to the domain you use to sign in to Zoho.
Create an app-specific password
If two-factor authentication is enabled on your Zoho account (it should be), Zoho requires an app-specific password for SMTP/IMAP — your normal password will be rejected.
- Sign in to Zoho and go to Settings → Security → App Passwords.
- Generate a new app password named something like "EmailWarmer".
- Copy the password — it's displayed once.
Pick your regional hosts
Use the region where your Zoho account lives. If you sign in at zoho.eu, use the .eu hosts; zoho.in, the .in hosts, and so on.
| Region | SMTP host | IMAP host |
|---|---|---|
| Global (zoho.com) | smtppro.zoho.com | imappro.zoho.com |
| India (zoho.in) | smtppro.zoho.in | imappro.zoho.in |
| Europe (zoho.eu) | smtppro.zoho.eu | imappro.zoho.eu |
| Australia (zoho.com.au) | smtppro.zoho.com.au | imappro.zoho.com.au |
Ports are the defaults: 587 for SMTP and 993 for IMAP.
The Add mailbox flow includes Zoho presets for each region — pick your region and the hosts and ports are filled in for you. You only need the table above if you're entering settings manually.
Connect the mailbox
- In the Add mailbox flow, choose SMTP/IMAP (or the Zoho preset for your region).
- Enter your email address and a sender name — the From name shown on warmup mail. Leave it blank and one is derived from your address.
- Enter the SMTP host and port for your region, your full email address as the username, and the app-specific password.
- Turn on use same credentials so IMAP reuses the same login, and confirm the IMAP host matches your region.
- Run the connection test. It performs a real SMTP verification and IMAP login — the mailbox isn't saved until both pass.
Troubleshooting
"535 Authentication Failed"
In order of likelihood:
- Wrong region. Check which domain you sign in on (zoho.com, zoho.in, zoho.eu, zoho.com.au) and match the SMTP/IMAP hosts to it.
- Using your account password instead of an app-specific password. With 2FA on, Zoho only accepts app passwords for SMTP/IMAP.
- Typo or stale app password. Generate a fresh one and paste it carefully.
SMTP passes but IMAP fails
Confirm IMAP access is enabled in Zoho Mail settings, and that the IMAP host region matches the SMTP host region — mixing smtppro.zoho.in with imappro.zoho.com will fail on the IMAP side.
Next steps
Once connected, configure warmup — daily volume, reply rate, working hours — following the quickstart, or dig into every option in the settings reference. To understand what happens after you hit Start, read how warmup works.