Is there somewhere where error messages are listed, with an interpretation of what they mean and advice about what you might do about the error?
I get
"In model 'multiCholACE' NPSOL returned a non-zero status code 1. The final iterate satisfies the optimality conditions to the accuracy requested, but the sequence of iterates has not yet converged. NPSOL was terminated because no further improvement could be made in the merit function (Mx status GREEN). "
I'm sure this is not the only error message I will come up against. I had a rootle around and could not find a place where such messages were listed, but I may have missed something.
The old Mx manual did have such a listing, but it was impenetrable to people who were not experts in optimization.