"Failed to use the skill due to an unknown reason."

Whenever I've had this, unequipping every 'summon' type item (android, pets, totems, ring) and then rebooting my computer has fixed it. It has happened without auto buff gems being on my character though so my conclusion earlier on in this thread isn't correct.

I think this is in some way related to the damage glitch, not sure how though, but the two seem to happen together.. however it could just be me =/

It's not just you I've been getting that damage glitch a lot in the past few days. I can't quite put my finger on it but I definitely think the two glitches are related and shadow partner has something to do with the damage glitch..

Anyway I finally got rid of "Failed to use the skill due to an unknown reason." I had unequipped all my gear and re-equipped it, then I shut my computer down and went out for an hour. When I went back on Maple I did not get the message. It could be from having my computer/maple off for a longer amount of time, or since it seems to be a server sided glitch, something in the server may have reset while I was out.