nlmefit hangs after 1st iteration

Hello, I'm using nlmefit and right off the bat it spits out some output, but then it jut sits there and nothing happens. I've been running the script for > 24 hrs

options = statset('TolX',1e-4,'Display','iter');
[Beta_hat, Psi_hat, stats, b_hat] = nlmefit(X,Y,group, [],model,beta0', 'REParamsSelect',1:R,...
        'FEParamsSelect',1:R*C,...
        'ApproximationType', 'RELME', ...
        'Options',options)

thanks or any help!!

[the cyclist]

I have never had nlmefit() hang like that. It is impossible to help diagnose this without more info.

Are you able to post the smallest possible set of data (X,Y,group,etc.) that exhibits the phenomenon you are seeing?

You can do things like cut your dataset in half (or more) and adjust your starting parameters to see if nlmefit() stops.