"Mailbox not found" error

This error means the mail server could not find an account matching the username you provided. The server is reachable and accepting connections, but the specific mailbox does not exist or is not recognized.

Common Causes:

1. Wrong username format — Your username must be your full email address (e.g., [email protected]), not just 'john' or a partial address. This is the most common cause.
2. Typo in email address — Double-check for misspellings, extra spaces, or wrong domain (e.g., @gmial.com instead of @gmail.com).
3. Email account disabled or deleted — The account may have been suspended, deactivated, or deleted by your email provider or domain administrator. Log in to your provider's web interface to verify the account is active.
4. Alias vs. primary address — Some providers only accept the primary email address for SMTP login, not aliases or distribution group addresses. Try using your primary mailbox address instead.

Provider-Specific Notes:

• Gmail — Your username is always your full Gmail or Google Workspace address.
• Outlook/M365 — Use your primary email address, not a shared mailbox or alias. Shared mailboxes require special configuration by your M365 admin.
• Hostinger — Use the full email address you created in Hostinger's email panel (e.g., [email protected]).
• Zoho — Use the primary address from your Zoho Mail account. Make sure you are using the correct regional domain (zoho.com, zoho.eu, zoho.in).
• Custom/self-hosted — Verify the account exists in your mail server's admin panel (Plesk, cPanel, etc.).

Debugging Steps:

1. Copy-paste your email address to avoid typos.
2. Log in to your email provider's webmail to confirm the account is active and accessible.
3. Check with your domain administrator that the mailbox has not been deleted or disabled.
4. If using a custom domain, verify that MX records are properly configured and pointing to the correct mail server.

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