Is one who recites Quranic verses without diacritics and makes mistakes in their recitation sinful?

You are correct in your pursuit of accurately reciting the noble verses, for it is impermissible to recite a Quranic word while doubtful of its correctness. And whoever frequently makes errors in recitation and is capable of learning, it is obligatory for him to learn before reciting; otherwise, he would be disobedient.