class RBF(nn.Module):
    def __init__(self,in_features,h_features,out_features):
        super(RBF,self).__init__()
        self.linear = nn.Linear(in_features,h_features,bias=False)
        self.Gaussian1 = Gaussian(h_features,out_features)
    
    def forward(self,x):
        x= self.linear(x)
        #x = Gaussian(x)
        self.Gaussian1(x)
        return x

You should call self.Gaussian1 instead of constructor of Gaussian class, so as to pass x into Gaussian.forward()