Grav can't create cache image

Hi,

In my theme if I enable cache for images, like this:

{{ page.media.images[image].cache.url() }}

Grav creates a fallback.jpg image with the red text "Error" for every image.

If I disable cache:

{{ page.media.images[image].url() }}

The images are shown correct as normal.

The site is hosted on Digital Ocean and GD is installed and enabled:

GD Support: enabled
GD Version: bundled (2.1.0 compatible)
GIF Read Support: enabled
GIF Create Support: enabled
PNG Support: enabled
libPNG Version: 1.2.49
WBMP Support: enabled
XBM Support: enabled

Do you have any suggestions to fix this? Thanks!

Did you already check https://learn.getgrav.org/troubleshooting/permissions ?

Thank you for your reply, I already asked the site owner to check the permissions but it didn't help, so he decided to move to a different hosting provider