Melee attack bug video included.

OneButtonDash

https://youtube.com/watch?v=CIUZW31Kv1Q

Not sure what causes this but it's happened to me a few times. I mainly dual wield in mostly assassin skills.

BoozeKashi

Look in Skill tree for that attack ability. Look at "Cost". Can't tell for sure, but from the video it sounds like you are using a Stamina based ability and it stops working when your stamina gets too low and you no longer have what it "costs". You are stuck without that attack until stamina regens.

If that is the case, look at where you can invest char/skill points to increase max stamina or regen, and combine that with foods/drinks/potions to try to avoid running out like that.

OneButtonDash

Nah that wasn't the issue, I wasn't able to even use my normal or light attacks, everything was jammed up. You can easily see in the video.

BoozeKashi

Sorry, just taking a guess because all I can hear very clearly is the loud clicking sound that happens when button is spammed but stamina is empty.