Hey,
so I installed a new website with concrete5 (latest version) today. Now I tried to delete all the sample images at once in the file manager. I selected all images and then tried to delete them.
Everytime I try it, an error message appears: "Error
Invalid form token. Please reload this form and submit again."
Example is attached as image.

Please help me, I don't know why this happens all the time, I already wiped the complete installation and installed it again.

Thanks to all
Sven