My server is on 1.15.2, and the mod's version is "Ma-Enchants-1.15.2-3.1.0". I know that this enchant might not work on big trees, but for me it doesn't work at all, even on simple trees. I have other mod installed, but the axe i used was a vanilla iron axe. I tested in singleplayer and it didn't work either. The other enchants are working perfectly.

You need to press key while mining tree to activate lumberjack. Check Excavate keybind in options by default it's "c"