Visual Editor broken on WordPress 4.7.4 – two accounts – different issues

Hello,

starting yesterday we encounter an issue with the visual editor in wordpress. We used to use the CKeditor which suddenly gave as nothing but white html on a white background in the textbox and no toolbar to work with.

When disabling the CKeditor the editing page started to load very slow to finally give the following error:

Another problem is that on our second account (2 Admins) the visual editor is not accessible at all. Only the HTML editing page can be accessed. Trying to switch to visual gives no reaction on the click and no page loading or whatsoever at all.

So we have two accounts – one with the displayed issue, one with no access at all to the VE.

Another side effect is that our Yoast SEO plugin started to look weird:

But I guess this is because it’s connected to the editor in order to give those SEO reccomendations. Nevertheless I wanted to mention it.

In order to solve the problem we:

• disabled all plugins with no effect (now enabled them again – all of them up to date)
• used different browsers (FF and Opera) with no changes
• cleared cache and cookies on both machines (and all browsers)
• logged out and back in to our both accounts
• re-installed WP 4.7.4
• replaced the tinymce files on our wordpress installation via ftp
• added define('CONCATENATE_SCRIPTS', false); to our wp-config

Nothing helped so far.

Another thing to mention might be that we do use cloudflare in order to protect our site. We run it on standard setup, meaning we created an account, use the free version and added their plugin to our WP setup – no costum adjustments whatsoever. On my research on the issue I came across reports that it might be releated. However, disabling the plugin did not give any effect (as mentioned before).

Our main content writer is now forced to work with my account since she is not able to acces the VE and we have to switch ownerships of an article after publishing it which is a very uncomfortable workaround.

Is there anything we can do to change the situation? Any help or suggestion is appreciated!

Thanks in advance!