one user gets this when clicking Mark Site As Read.

He's doing something and his session has already expired, sat idle for too long.  

	/**
	 * CSRF Check
	 *
	 * @return	void
	 */
	public function csrfCheck()
	{
		if ( !\IPS\Login::compareHashes( (string) $this->csrfKey, (string) \IPS\Request::i()->csrfKey ) )
		{
			\IPS\Output::i()->error( 'generic_error', '2S119/1', 403, 'admin_csrf_error' );
		}
	}

 

well he does it often. he has reported it several times (the only person to report it)   

Sounds like it might be something with his browser.  If I recall correctly, and I could be completely wrong here, the csrfKey is stored as a cookie.  If he's got some software in his browser that's blocking or destroying cookies might be the reason. 

It definitely sounds like something on the users machine, though.  You could always submit a ticket to IPS and they might be able to give you a bit more insight.  

I receive this same error or this one:

I run into it with Edge, Chrome, and Firefox.

The CSRF protection key did not match. This may indicate a plugin or theme is out of date. Please contact technical support for more information.

Error code: 2S119/1

 

Not sure, a while back I installed a new local 4.3 version, uploaded a theme and myself got this error. Nothing in my themes were out of date either. I went ahead and uploaded the rest of my themes then installed a new 4.3 local version and uploaded those xml files into the new version and everything was then ok. I know that don't help you but in case someone reads this that can look into it.

Have you.... Submitted a ticket?

also make sure any 'bookmarks' are not referencing http but rather https too