There can be various reasons that could have generated such an error and nothing can be firmly said about why you got such an error.
Did you try deleting the articles again ? If not then try doing so and check if you get the same error. Also, check if you face the same issue while trying to delete a single post.
Well, if you still get the same error I’d suggest you to get in touch with your host immediately and seek assistance. It may be a server configuration issue where the particular function might have been blocked over the server.
