Mplus潜类别分析时模型报错

样本量5000，四个分类变量进行分析，1—3类别时没有报错，四类别时报错如下，但是结果正常跑出来了，是否可信
THE STANDARD ERRORS OF THE MODEL PARAMETER ESTIMATES MAY NOT BE TRUSTWORTHY FOR SOME PARAMETERS DUE TO A NON-POSITIVE DEFINITE FIRST-ORDER DERIVATIVE PRODUCT MATRIX. THIS MAY BE DUE TO THE STARTING VALUES BUT MAY ALSO BE AN INDICATION OF MODEL NONIDENTIFICATION. THE CONDITION NUMBER IS -0.220D-16. PROBLEM INVOLVING THE FOLLOWING PARAMETER: Parameter 19, [ C#3 ]

 ONE OR MORE PARAMETERS WERE FIXED TO AVOID SINGULARITY OF THE

 INFORMATION MATRIX. THE SINGULARITY IS MOST LIKELY BECAUSE THE

 MODEL IS NOT IDENTIFIED, OR BECAUSE OF EMPTY CELLS IN THE JOINT

 DISTRIBUTION OF THE CATEGORICAL VARIABLES IN THE MODEL.

 THE FOLLOWING PARAMETERS WERE FIXED:

 Parameter 16, %C#4%: [ OPA$1 ]

 Parameter 17, [ C#1 ]

 Parameter 18, [ C#2 ]