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Dropboxcaptcha.com is blocked. Cannot log on to Dropbox

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When I try to logon to Dropbox I get this message: "Your browser appears to be blocking dropboxcaptcha.com, which is required for authentication. To resolve this issue, please update any anti-virus or ad-blocking software settings to allow connections to dropboxcaptcha.com."

Where and what should I add to get this sorted? Thanks Mo

When I try to logon to Dropbox I get this message: "Your browser appears to be blocking dropboxcaptcha.com, which is required for authentication. To resolve this issue, please update any anti-virus or ad-blocking software settings to allow connections to dropboxcaptcha.com." Where and what should I add to get this sorted? Thanks Mo

All Replies (3)

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I have enabled the Popup Blocker and added an exception for DropboxCaptcha.com but it doesn't make any difference. I still can't login to Dropbox and the message is persistent.

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Did you try Firefox in Safe Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#search104

I was able to log into DB, but did not get any captcha.

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You can check for issues with Total Cookie Protection.


If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, DuckDuckGo PE, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

Firefox shows a purple shield instead of a gray shield at the left end of the location/address bar in case Enhanced Tracking Protection is blocking content.

  • click the shield icon for more detail and possibly disable the protection

You can check the Web Console for relevant-looking messages about blocked content.


You can try these steps in case of issues with webpages:

You can reload webpage(s) and bypass the cache to refresh possibly outdated or corrupted files.

  • hold down the Shift key and left-click the Reload button
  • press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
  • press "Command + Shift + R" (Mac)

Clear the Cache and remove the Cookies for websites that cause problems via the "3-bar" Firefox menu button (Settings).

"Remove the Cookies" for websites that cause problems:

  • Settings -> Privacy & Security
    Cookies and Site Data: "Manage Data"

"Clear the Cache":

  • Settings -> Privacy & Security
    Cookies and Site Data -> Clear Data -> [X] Cached Web Content -> Clear

Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

  • switch to the Default System theme: "3-bar" menu button or Tools -> Add-ons -> Themes
  • do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window