This plugin has not been updated by its developer since a long time ago.
It could imply partial or total lack of compatibility with the latest versions of b2evolution.
Chessboard render is a plugin for B2evolution blogs that converts FEN (Forsyth-Edwards Notation) notation or an alternative 8×8-layout to a chessdiagram using HTML with 8×8 images. Options include a border and a subset of an 8x8 chessboard. The images are provided with the plugin. You end up with a chessdiagram depicting your position. If you ever want to blog about chess, this is the plugin you're after.