Allah is capable of doing everything as He is the creator of the Heavens and the earth.
However, this relates to the possible and not the impossible.
If someone says: can Allah create something he can't move? We say that this is a stupid question! If Allah created it, Allah can move it. But the essence of your question is originally not correct and it is not this.
Your question is: can Allah be incapable of doing something? This is not possible!
A Da'ee said he can list a 1000 things that Allah cannot do, is this kufr?
Can Allah create man-made creations like computers, vehicles etc?
Can Allah create something all hearing & all seeing?