Can´t add new CMS Content in Editor

Hello !

I have set up a Blog-CMS System for a Client of mine and wanted to try if i can add new Blog Posts
in the Editor. Since like a few Days, i am not able to click the Button “Create”. I´ll send a Image so you can see. The Button is not clickable.

Best regards!


Here is my site Read-Only: LINK
(how to share your site Read-Only link)

I figured out, that this only occurs, when i uploaded an image from external files…But i don´t know why.