Gmail IMAP Not Working — What It Means & How to Fix It

What Does This Error Mean?

Gmail IMAP is failing to connect in your email client such as Outlook, Apple Mail, or Thunderbird. This is usually caused by IMAP being disabled in Gmail settings, or your email client using a regular password instead of an App Password. Your emails are safe — this is a configuration issue, not data loss.

Affected Models

Gmail Web
Microsoft Outlook
Apple Mail
Mozilla Thunderbird
All Gmail accounts

Common Causes

IMAP access is disabled in Gmail settings — it is not enabled by default for all accounts
Two-Factor Authentication is enabled on the Google account but the email client is not using an App Password
The email client is using the wrong IMAP server address or port number
Google has blocked the sign-in attempt because the email client is using Less Secure App access (deprecated)
A recent Google security alert blocked the third-party email client connection

How to Fix It

In Gmail on the web, click the Settings gear → See all settings → Forwarding and POP/IMAP tab → confirm IMAP is set to Enable IMAP → Save Changes.

IMAP must be explicitly enabled in Gmail settings — without this step, no external email client can connect, regardless of other settings.
If your Google account has 2-Step Verification enabled, go to myaccount.google.com → Security → App Passwords and generate an App Password for your email client.

Modern email clients cannot use your regular Google password when 2FA is active — an App Password is a separate 16-character password generated specifically for the app.
In your email client, enter these exact IMAP settings: Server: imap.gmail.com, Port: 993, Encryption: SSL/TLS.

Using the wrong port (such as 143) or the wrong encryption type is a very common cause of IMAP connection failures.
Check your Gmail inbox for a security alert from Google about a blocked sign-in attempt — click the link in that email to allow access.

Google sends a security email when an unfamiliar app tries to connect — you must approve this the first time each new client connects.
Remove the Gmail account from your email client completely and add it again from scratch using the new App Password.

Cached incorrect credentials can prevent reconnection even after you change your password — a clean removal ensures the new settings take effect.

When to Call a Professional

Gmail IMAP issues are configuration problems that are fully self-fixable. If you are setting up Gmail IMAP on a company-managed device, your IT administrator may need to authorize the email client. Google Workspace accounts may have IMAP disabled by the organization admin — contact your admin if personal account steps do not apply.

Frequently Asked Questions

What is the difference between Gmail IMAP and POP3?

IMAP syncs your emails across all devices — reading on your phone marks it as read on your computer too. POP3 downloads emails to one device and typically deletes them from the server. For most users, IMAP is the better choice since it keeps all devices in sync.

Why did Gmail IMAP stop working after I turned on 2-Step Verification?

Enabling 2FA breaks the connection for email clients that use your regular password. You need to generate an App Password at myaccount.google.com and use that in your email client instead. The App Password is a one-time setup and does not expire unless you revoke it.

What are the correct Gmail IMAP server settings?

Incoming (IMAP): imap.gmail.com, port 993, SSL/TLS. Outgoing (SMTP): smtp.gmail.com, port 465 (SSL) or 587 (TLS). Username is your full Gmail address including the @gmail.com part.