Unknown glyph found in prefix

hey guys, i have no idea what this mean.

It looks like your feature code contains glyphs that aren’t present on export. Go to Font Info > Features and click Update.

Unfortunately nothing happens when I click on update, i tried to update them piece by piece but somehow nothing happens.

Did you write those features? Where does this code come from?

You can delete the prefix.

After I deleted the error signs my variable font look like this:

It was some problem with the nodes!