[Plugin: NextGEN Gallery] Thumbnail editor is blank

Hey guys,

i need help very seriously.
I googled 6 Hours and i found many things but not exact my problem.

if hit the change thumbnail button the popup comes up but its blank.
No erorr nothing. If i upload a new picture thubnail is generatet perfectly. Just the self edit doesnt work. Many people have promlems with croping but my problem is there is no croping. The Popup is blank.
I found this:

https://www.ads-software.com/support/topic/plugin-nextgen-gallery-nextgen-gallery-edit-thumbnail-editor-blank?replies=13

The problem is the same but the solutions doesnt work for me.

My version is:
Version 1.8.3

What i did:
– Update Nexgen to the newest
– Downgreaded Plugin downt to 1.7.1
– Put the upload max to 90MB via .htaccess
– switched on and off the permalink option on wordpress
– deaktivated all plugins

Nothing Helped.
So guys i hope you can help. Man i am down…..

Kindes regards 12557

https://www.ads-software.com/extend/plugins/nextgen-gallery/