Uploading images "An Error occurred in the upload. Please Try again later."

Hi,

Yesterday i transfered my website to another hosting, the domain name is still the same, only the hosting changed. The whole website is working fine, only uploading images is not possible anymore. I keep getting the error-message “An Error occurred in the upload. Please Try again later.”

But when i go to by upload-folder by ftp, i can see that the file is uploaded in the correct folder, but no thumbnails are made…
Permissions on my upload folder are set on 755 and the uploaded files get the 644-permission.

I tried everything based on what i found on the internet but still i have no solution for this.
Deactivated my plugins, changed the theme, updating my wordpress, updating all plugins, …

I hope anyone can help me with this problem. Is it possible that the adjustments on my hosting are not correct?

Thanks!!