No such column of Knowledge__kav even if exiting it.

Even if Exiting the custom filed name as like below, But you will get some error. 
" No such column 'Step_Auto_Article_c' on entity 'Knowledge__kav'. If you are attempting to use a custom field, be sure to append the '__c' after the custom field name. Please reference your WSDL or the describe call for the appropriate names."

Knowledge of custom field names. 

 

Here is an example,  

In that case, you have to check "Set Field-Level Security"  whether you turn on your group account or not of