Dua is not accepted by those who consume haram (prohibited)

The Messenger of Allah ﷺ said: "O people, Allah is Good and He therefore, accepts only that which is good. And Allah commanded the believers as He commanded the Messengers by saying: "O Messengers, eat of the good things, and do good deeds; verily I am aware of what you do" (xxīi. 51). And He said: "O those who believe, eat of the good things that We gave you."

He then made a mention of a person who travels widely, his hair disheveled and covered with dust. He lifts his hand towards the sky: O Lord, O Lord, "whereas his diet is unlawful, his drink is unlawful, and his clothes are unlawful and his nourishment is unlawful. How can then his supplication be accepted?"

قَالَ رَسُولُ اللَّهِ ﷺ: «أَيُّهَا النَّاسُ إِنَّ اللَّهَ طَيِّبٌ، لاَ يَقْبَلُ إِلاَّ طَيِّبًا۔ وَإِنَّ اللَّهَ أَمَرَ الْمُؤْمِنِينَ بِمَا أَمَرَ بِهِ الْمُرْسَلِينَ» فَقَالَ «{ يَا أَيُّهَا الرُّسُلُ كُلُوا مِنَ الطَّيِّبَاتِ وَاعْمَلُوا صَالِحًا إِنِّي بِمَا تَعْمَلُونَ عَلِيمٌ }» وَقَالَ «{ يَا أَيُّهَا الَّذِينَ آمَنُوا كُلُوا مِنْ طَيِّبَاتِ مَا رَزَقْنَاكُمْ }»

ثُمَّ ذَكَرَ الرَّجُلَ يُطِيلُ السَّفَرَ أَشْعَثَ أَغْبَرَ يَمُدُّ يَدَيْهِ إِلَى السَّمَاءِ يَا رَبِّ يَا رَبِّ «وَمَطْعَمُهُ حَرَامٌ، وَمَشْرَبُهُ حَرَامٌ، وَمَلْبَسُهُ حَرَامٌ، وَغُذِيَ بِالْحَرَامِ، فَأَنَّى يُسْتَجَابُ لِذَلِكَ؟»