HTTP Load error in Media/ Thumbnail missing

Hi support, on my site , I start Having problems loading jpg of less that the 1MB .
It generates HTTP load failure message while Uploading through the Media / Add new facility.
. If loaded , then I cannot see the thumbnail.
- I have tried to regenerate Thumbnail with the plugin of that name. It does not work
- I renamed jpg in png . It does not work
- I erased the file from the Media Library , Resize it (with Paint) to a max size that fit the WP settings . It does not work.
- via FTP , I set permissions to the uploads directory and recursively to 744 and set the files permissions to 644 .It does not work

What I can notice is when uploaded, if the Media Library description does not entice the dimensions in pixels then the thumbnail is not showing ...
Any idea how to fix this .
You have access to the platform .
Fell Free to play with the attached file.