The DateTimeS (string field) could not be used to create a DateTime field. The Convert Time Field tool, which is used to do the conversion, failed because of the input date values.
Inspect the values inside the DateTimeS (string field) and ensure they represent a valid time format. Manually convert the DateTime values using either the Convert Time Field tool, or use Python parsing with Add Field and Calculate Field tools to make a date field.
Alternatively, if a date field is not required, do nothing and use the DateStringS field as a String type.