I am trying to run a two-level regression analysis for a continuous dependent variable with a random slope. The model is running, but I get this warning: THE MLR STANDARD ERRORS COULD NOT BE COMPUTED. THE MLF STANDARD ERRORS WERE COMPUTED INSTEAD. THIS MAY BE DUE TO NEAR SINGULARITY OF THE RANDOM EFFECT VARIANCE/COVARIANCE OR INCOMPLETE CONVERGENCE.
Can you tell me what this warning means and if I should be worried about it? Is there anything I can do to solve this?