Provider guide · Zoho Mail
Zoho's settings depend on what kind of account you have: personal accounts and organisation accounts on their own domain use different servers, and accounts hosted in different data centres use different hostnames again. Identify your case first and the rest is quick.
1 · Credentials
The username is always the full email address. The password and the host depend on two questions: does the account use two-factor authentication, and is it personal or organisational?
If two-factor authentication is on, and it should be, your account password will be refused over SMTP. Zoho wants an application-specific password:
Choose Application-Specific Passwords, then Generate New Password, and name it, for instance “WordPress”.
Zoho does not display it again.
Without two-factor authentication the account password works as is, though Zoho itself recommends app passwords for mail clients either way.
2 · In the plugin
Selecting the Zoho preset fills the server (smtp.zoho.com), the port (587) and the encryption (TLS). For some accounts, that host needs one edit.
Personal account, an address ending in @zoho.com or @zohomail.com: keep smtp.zoho.com as filled. Organisation account, your own domain hosted at Zoho: change the host to smtppro.zoho.com, same port, same encryption.
The full address, and the app password, or the account password without 2FA.
The account’s own address or one of its configured aliases; Zoho matches the From against the authenticated account.
Save, then use Send Test Email. If the connection refuses to open at all, read the last pitfall below about data centres before blaming the password.
3 · Pitfalls
All three Zoho pitfalls are variations of the same theme: the right settings for a slightly different account than yours.
An address on your own domain hosted at Zoho goes through smtppro.zoho.com, not the smtp.zoho.com the preset fills for personal accounts. Symptoms of the mismatch are authentication errors with a perfectly good password. One host edit fixes it.
Two-factor accounts cannot use their account password over SMTP at all; Zoho requires an application-specific password, generated under accounts.zoho.com, Security. Organisations signing in through SAML single sign-on are in the same boat. The generated password is shown once, and deleting it revokes WordPress without touching anything else.
Zoho hosts accounts in regional data centres, and the mail hosts follow: an account on Zoho’s European infrastructure authenticates against smtp.zoho.eu, or smtppro.zoho.eu for an organisation, and the .com servers refuse its perfectly good credentials. The authoritative values for your exact account are in Zoho Mail’s own Server Configuration Details screen; when in doubt, trust that screen over any guide, this one included.
The email log keeps the exact error message the server returned, which is the fastest route to the cause. The documentation walks through the common ones.
There is a guide like this one for each of the twelve presets, from Gmail to Amazon SES, and the plugin takes any other SMTP server too.