File Upload failing

This is what I get after attaching a file and pressing "Post Discussion"
I'm running Vanilla 2.6.4 on an Ubuntu server running version16.04.5 LTS (Xenial Xerus) and PHP version 7.1.20
Any ideas?
1
This is what I get after attaching a file and pressing "Post Discussion"
I'm running Vanilla 2.6.4 on an Ubuntu server running version16.04.5 LTS (Xenial Xerus) and PHP version 7.1.20
Any ideas?
Comments
The FileUpload plugin comes with a MediaModel which doesn't respect the DatasetType and therefore returns an Object instead of the Array that is expected.
Deactivate the FileUpload plugin (not needed when using the Advanced Editor) and if it does not work right after that, delete the files in /cache