unable to use spells or monster effects]
[color=#3AADE4]Bug reproduction steps[/color]
Start a duel]
your replay code
[color=#3AADE4]Screenshot OR error code[/color]
should had been able to play]
To help shed some more light on this, what settings are you using in the duel? What rule set are you using, game mode, and are you playing against a player opponent or an AI? The more information you give, the more effective the team be can try to pin down a solution.
Also, I’ve heard the servers have been inconsistent lately so that could also be a factor into the cause of all of this. It is an open beta.