Is my grapevine dying it has gone brown and It's leaves are dropping off Have I got it in to big?

... when I bought it I put it in a very big pot 30 or 40 gal or:... when I bought it I put it in a very big pot 30 or 40 gal

... when I bought it I put it in a very big pot
30 or 40 gal

or:... when I bought it I put it in a very big pot 30 or 40 gal

Tags:pot,dying,