Error : no gpu

first, I submit a solution and run out of time, which is quite wired, because it takes only 1 hour to run on my computer.
then I submit another solution, force it use only gpu. it said
"Found no NVIDIA driver on your system. Please check that you have an NVIDIA GPU and installed a driver"

Your code must be supported for CUDA + Put gpu:true in aicrowd.json
If you still have the problem then only @shivam can help you.