Hi Vitaliy1993,

Some users have reported similar issues with logging in to vk.com that were resolved by giving the site access to their cookies. Here is how to do this:

1. Navigate to about:preferences#privacy in your address bar.
2. Scroll down to Cookies and Site Data and click on the Manage Permissions Box.
3. Now type in the exact address of the website you want to give permission to, in your case it should be vk.com. Click on Allow and Save Changes.

Try to log in and see if you're still having the issue.

Didn't help..

Note that you need to add the proper protocol (likely https:// in this case) when you create an allow exception.

You can also do this via "Tools -> Page Info -> Permissions".

cor-el said

Note that you need to add the proper protocol (likely https:// in this case) when you create an allow exception. You can also do this via "Tools -> Page Info -> Permissions".

I typed full adress there, with "https://"

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

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows the shield icon at the left end of the location/address bar in case Content Blocking is blocking content.

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

You can check the Web Console about what content is blocked

• "3-bar" menu button or Tools -> Web Developer
• https://support.mozilla.org/en-US/kb/content-blocking

cor-el said

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

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows the shield icon at the left end of the location/address bar in case Content Blocking is blocking content.

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

You can check the Web Console about what content is blocked

• "3-bar" menu button or Tools -> Web Developer
• https://support.mozilla.org/en-US/kb/content-blocking

I tried to reproduce it with all content blocking programs disabled - that didn't help. Also I tried to reproduce it on Edge from Microsoft- all fine there.

Have you tried it in safe mode yet?

If Firefox is open, you can restart in Firefox Safe Mode from the Help menu:

• Click the menu button , click Help and select Restart with Add-ons Disabled.

If Firefox is not running, you can start Firefox in Safe Mode as follows:

• On Windows: Hold the Shift key when you open the Firefox desktop or Start menu shortcut.

When the Firefox Safe Mode window appears, select "Start in Safe Mode".

To exit Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

Safe mode didn't help. Also I tried refreshing Firefox previously...