530 5.7.0: Must issue a STARTTLS command first

AnySMTP

The error usually looks like this:

530 5.7.0 Must issue a STARTTLS command first.

What it means

The server requires an encrypted connection, but your app tried to continue without enabling encryption.

Common causes

  • The app is set to no encryption (or “None”) on a port that requires STARTTLS, such as 587.

How to fix it

  1. Set your app’s encryption to STARTTLS (or TLS) for port 587, or SSL/TLS for port 465.

Tools to help diagnose it

Email server checker

Check any IMAP, POP or SMTP server’s encryption, certificate and supported sign-in methods

Email server settings finder

Find the IMAP, POP, and SMTP server names, ports and encryption settings for any email address

SMTP connection tester

Spin up a real SMTP test server and diagnose your email sending configuration in real time

A free tool provided by Auth-Email

Auth-Email makes your Gmail, Outlook, or other OAuth 2.0 email account available to any IMAP, POP3, or SMTP email client — no app passwords or special configuration needed.

Read the docsTry Auth-Email →

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