Gmail Sign-in Popup Blocked or Missing in Firefox

When Gmail's sign-in window never appears in Firefox, the browser's popup blocker or a privacy extension is usually the cause. The Google sign-in flow opens a separate small window, which Firefox treats as a popup by default.

Here's how to fix it: adjust Firefox's popup exceptions, third-party cookie settings, and extension permissions so the Google sign-in window shows again. The steps use the desktop menu path through Settings, Privacy and Security, and Permissions.

In this guide, I have covered:

Why Gmail’s sign-in popup may be blocked or missing in Firefox

When you click Sign in on Google, Gmail opens a separate sign-in window through accounts.google.com. Firefox treats that small OAuth popup as a regular pop-up window, so its built-in blocker can stop it before you ever see it.

The usual culprit is Firefox’s Block pop-up windows setting, which is on by default and has no exception for Google. A popup-blocking extension, strict Enhanced Tracking Protection, or blocked third-party cookies can also keep the Gmail sign-in window from completing.

Allow the popup from Firefox’s blocked-popup notification bar

When Firefox blocks a popup, an info bar slides in at the top of the page. It names the blocked site and gives you an options menu, so you can allow that specific popup without touching the global settings. We usually start here because it is the fastest fix.

1. Open the Gmail tab and try the sign-in step again so Firefox registers the blocked popup.
2. Look at the top of the current tab for an info bar that says accounts.google.com was prevented from opening a pop-up window.
3. Open the bar’s options menu and choose Allow pop-ups for accounts.google.com, or choose the option to edit pop-up blocker preferences for the site.
4. Click the Gmail Sign in button again to confirm the popup now opens.

You’ll know it worked when the Google sign-in window appears on top of the Gmail tab and you can pick your account.

Add Google account domains to Firefox’s popup exceptions list

If the notification bar does not show or you want a permanent fix, add the Google account domains to Firefox’s popup exceptions list. Mozilla’s own popup-blocker guide lists the same domains at Mozilla’s pop-up blocker troubleshooting page.

1. Click the hamburger menu at the top right of Firefox.
2. Choose Settings from the menu.
3. Pick Privacy & Security in the left sidebar.
4. Scroll down to the Permissions section.
5. Confirm Block pop-up windows is checked, so you keep blocking popups on other sites.
6. Click the Exceptions… button next to it.
7. Type https://accounts.google.com in the Address of website field and click Add.
8. Optionally add https://mail.google.com the same way.
9. Click Save Changes and close the dialog.

You’ll know it worked when Gmail’s sign-in button opens accounts.google.com without Firefox asking permission, and you reach the Google account picker.

Adding https://mail.google.com is helpful if you switch between multiple Google accounts in Gmail. https://accounts.google.com alone is enough for a single first sign-in.

Allow third-party cookies for Google sign-in

Google’s sign-in flow sets a cookie inside the popup and then reads it back in the Gmail tab. If Firefox blocks third-party cookies for accounts.google.com, the popup can load but the sign-in never finishes. That often looks like a missing popup or a sign-in loop.

Start by checking Enhanced Tracking Protection. If it is set to Strict or Custom with cookies blocked, change it to Standard. Then add a site-specific exception below so Google’s cookie can be read back in the Gmail tab.

1. In the same Privacy & Security panel, check Enhanced Tracking Protection. If it is set to Strict or Custom with cookies blocked, change it to Standard.
2. Scroll to Cookies and Site Data and click Manage Exceptions….
3. Enter https://accounts.google.com, set the permission to Allow, and click Save Changes.
4. Close and reopen the Gmail tab, then try signing in again.

For a deeper walkthrough of cookie settings, see the Firefox cookie settings guide on BrowserHow. If your cookies keep getting wiped on browser exit, the Firefox cookies and cache guide explains how to keep them.

TIP: If you only sign in to Google from the Gmail tab, switching Enhanced Tracking Protection to Standard globally is faster than adding exceptions. Standard still blocks known trackers while leaving third-party cookies on for most sites.

Temporarily disable popup-blocking extensions

Privacy and ad-blocking extensions can stop the Gmail popup even when Firefox’s own blocker is off. Disable them one at a time to find the one causing it.

1. Click the hamburger menu and select Add-ons and themes.
2. In the left sidebar, click Extensions.
3. Use the blue toggle next to each extension to disable it. Start with ad blockers, tab managers, and any extension you installed in the past few weeks.
4. Restart Firefox from the hamburger menu .
5. Use Firefox normally for a few minutes, then check about:performance. If usage dropped sharply, re-enable extensions one by one to find the offender.

You’ll know it worked when the Gmail sign-in popup opens cleanly with extensions disabled. Re-enable them one by one until the popup stops working again. Then keep that extension disabled or add its allow-list entry for Google.

Test the sign-in flow in Troubleshoot Mode

If the popup still fails after checking extensions, Firefox’s Troubleshoot Mode is the cleanest way to see whether Firefox itself is the cause. It restarts the browser with extensions, themes, and custom settings temporarily disabled.

1. Click the hamburger menu at the top right of Firefox.
2. Click Help.
3. Select Troubleshoot Mode….
4. Click Restart in the confirmation dialog.

You’ll know it worked when Gmail’s sign-in window appears in Troubleshoot Mode without any changes. If it does, the problem is an extension, theme, or user stylesheet, and you can re-enable features in batches to narrow it down.

Refresh Firefox as a last resort

If the popup is still missing after all of the above, a Refresh restores Firefox to its default state while keeping your bookmarks, passwords, and browsing history. Use it only as a final step.

1. Click the hamburger menu , choose Help, then select More Troubleshooting Information.
2. On the Troubleshooting Information page, find the Give Firefox a Tune Up section on the right.
3. Click Refresh Firefox and confirm by clicking Refresh Firefox in the dialog.
4. Wait for Firefox to restart. Your bookmarks and logins are preserved, but extensions and most site settings are reset.

After the refresh, revisit the Gmail tab and complete the sign-in. You will need to re-add your popup exceptions under Settings, Privacy & Security, Permissions because the reset clears site permissions.

If the popup fails only on Google and not on other sites, Google’s side may be involved. Clearing your browser history can help, and the Firefox history clearing guide walks through it.

RELATED: View Site Info and Set Site Settings in Firefox on the Computer