I'm using Latent Gold Choice to estimante a LC model. The model performs well when up to three classes are considered. However, when I try with four classes I got a message of no convergence ("estimation procedure did not converge, 25 gradients larger than 1.0E-3) and maximum number of iterations reached without convergence. Anybody knows the possible reasons? Mis-specification of the model? A large number of observations (in my case 250000 obs)? Something else?