DistributedDataParallel - nccl issue

Sorry if this sounds ignorant but I am really new to pytorch. I am trying to use DistributedDataParallel but this error appears: ValueError: Invalid backend, only NCCL and GLOO backends are supported by DistributedDataParallel

I have already installed nccl but the error persists. Thanks a lot for your help in advance

autoencoder = nn.parallel.DistributedDataParallel(autoencoder.cuda(), device_ids=[0, 1, 2, 3])