Unsuccessfully means that something doesn't work out the way that you hoped it would. It can also mean that you don't achieve your goals.
The experiment was unsuccessful because the results were inconclusive.
Her attempt to start her own business was unsuccessful.
ADV
without success
1
The plan was singularly unsuccessful.
2
The subjugation of the tribe was unsuccessful.
3
The intention generally accompanies the unsuccessful.
4
Because of these impediments, the attempt was largely unsuccessful.
5
I searched at the height of the mania and was unsuccessful.
6
Supreme is unsuccessful and is poisoned by the Homeboys in the cafeteria.
7
His pistol misfired and the attempt was unsuccessful.
8
The attempts to stop the fire were unsuccessful.
9
A tax abatement sought from the city was unsuccessful.
10
Because of the unsuccessful season the club became defunct.