It happened to me exactly the same. I had to reinstall wordpress. But not just any version, certainly the latest update of dooplay 2.4.1 has that bug with wordpress 5.5.X. Even with versions 5.4.2 and 5.4.1 there is another error that the pages external to the theme do not load correctly. The solution was to try different versions of wordpress until arriving at the correct one. I highly recommend using the WP Donwgrade plugin for that purpose.