Stylegan2 2xGpu CRASH

I’m trying to train a custom_dataset on stylegan2 with 2x 1080 ti.

when I run the code with “–num-gpus = 1” everything goes well and the training starts.

when I run the code with “–num-gpus = 2” the code stops after
"Building TensorFlow graph …
Initializing logs …
Training for 10000 kimg … "

Edit: there is no crash log. the terminal just stay there forever doing nothing. to close the process i need to force the terminal to exit

what could be the problem?