1 elements are distorted. Either the isoparametric angles are out of the suggested limits or the triangular or tetrahedral quality measure is bad. The elements have been identified in element set WarnElemDistorted?
Have you run the model and found this error? There should be an element set called "WarnElemDistorted" in the odb (output database file). Highlight that set and see which elements are distorted. You may then be able to use the mesh control functions to alter the element spacing etc in that region. Alternatively, if you only have a warning, you may have some results that you can look at. Abaqus will not run if there is an error, but it will run if with warnings. The user has to decide whether the warnings are likely to affect the model results of interest.