Impress slides are blank in presentation mode

I use a dual-boot with both windows 10 and Ubuntu 20.04. I created a presentation in LibreOffice Impress (v6.4) in windows, where it worked as expected. In Linux, I opened the same file, but when I entered presentation mode, the slides where blank. I created another presentation, this time in Linux, and the same problem occurred: the screen is blank when I open presentation mode. It works fine in windows. Any advice would be appreciated, although since I can still open the presentations in windows, this isn’t the end of the world.

There might be a problem with initial install in Ubuntu 20.04, but I’m not experienced in this. See this question, Cannot print anything, exporting to PDF produces blank PDF