I'm using Moodle 3.5.2+ (Build: 20181023) and I've been having problems uploading files using moodle's own tools for several days now, either by adding a file resource using the add file button where when I see that it has uploaded up to 100% the browser remains in an infinite loop (I've checked in Chrome and Mozilla). (See image 1)
If I use the option "You can drag and drop files here to add them" then I see how they upload pdf files but then they are deleted automatically appearing the error message when connecting to the server. With other files until a couple of days ago also had problems but now only with PDF. It is very rare because I can upload txt, doc, or jpg. (See image 2)
When uploading PDF files with the Drag & Drop option it turns out that when uploaded it is deleted and the error message appears "error conecting to the server". See image 3
As a teacher I have solved it by uploading the files to a repository I have in Moodledata by FTP and then I can add them to the course without problems.
But the main problem is that the students in the Assignments cannot upload PDF files which I would like to solve.
I've been experiencing these problems since the last Moodle updates, I didn't have them before.
I appreciate any suggestion or help,