Hi, I'm having some troubles with the avatars in a openproject installed in a linux docker container. When uploading a picture for a custom avatar the file selection and preview of the avatar is ok, however it pop ups a error "Error saving the file" when applying the changes. This error happens in the admin account as well as the users accounts.

The "Enable user gravatars" and "Enable user custom avatars" are both enabled in the configuration of the avatar plugin extension. The default user gravatars work. So, the trick I saw in a previous thread doesn't work. It just seems to be a problem of uploading a new file for a custom avatar. 

Also tried setting the name to the host with 'localhost:8080' and '192.168.44.18:8080', but same error.

Any idea or configuration missing? Thanks for the help.