Since Connections 6.0 CR5 , was released there was also an update of the great optional editor formerly know as Ephox now named TinyMCE 5.
I love this editor ( and my customers love it too) because all the features available, so I usually add it to all my Connections setup.
In almost every cases the setup is very easy because to perform the setup it's needed only to run a script and install an EAR on the appserver but in some cases due particular SSH config, it could be required the manual setup.
During my last CR5 upgrade I wasn't able to use the script so I've followed the manual setup like it's written on IBM Documentation at this page..
After the setup , I've restarted Connections that become unusable with most of the widgets unable to be loaded and inside my logs I had something similar of what it's described by this technote . :
uncaught exception: Missing config.js in customization directory
404 Not Found 817ms ?includ...ariant= (line 6525)
"NetworkError: 404 Not Found - https://yourname.dev.acme.
This ponted me to another of my environments where I've upgraded the editor using the script where I've noted the setup directory was renamed by the installation scropt ... with the new name !
unfortunately the IBM documentation , wasn't upgraded totally because title talk about TiniMCE but the installation path mentioned is still the old one
To fix the issue, rename ephox folder in tiny and restart again Connections (or common app)