"Files" appears empty on my iPhone

Hello, since 3 weeks aproximately I can't access my files. I just open the icon and it says that there are no recent documents (and I used to use it every 2-3 days)

I can't even save more things. When I connect it to a mac computer it appears that it has things inside but I can't open them anyways

IOS is 15.5

Hope to get a solution

thanks