training of time delay neural network frozen at start

Hello,

I'm creating and training network only from command windows and scripts. I have set these parameters:

net.trainParam.showWindow=false;
net.trainParam.showCommandLine=true;

Sometimes, at the beginning of the training, it keeps frozen at the message:

Training Time Delay Neural Network with 'trainingFcn'.

I have the same issue (only occasionally,1/30) with several training functions: trainlm, trainbr, etc.

The nets are created with random values within certain limits. For now, I have max 3 hidden layers with max 3 nodes per layer, training in 1400 length concurrent data, with 3 inputs. All this in R2018a in ubuntu 18.04

I also have defined:

net.trainParam.time=60*5;

But when stuck, it doesn't seem to matter.