What is the ruling on congregational prayer behind a muezzin who does not recite well and prevents worshippers from entering the mosque after the prayer, with the presence of unpleasant odors in the mosque?

If the muezzin makes a melodic mistake (lahn) in the Adhan that alters the meaning, then his Adhan is invalid. However, if the mistake does not alter the meaning, or if it is merely a lack of good voice, then his Adhan is valid.

If the Imam makes a melodic mistake (lahn) in Al-Fatiha that alters the meaning, then his prayer and the prayer behind him are invalid. However, if the mistake does not alter the meaning, then his prayer and the prayer of those praying behind him are valid.

It is obligatory to advise the Imam and the muezzin in a kind and polite manner regarding the mistakes they make, and regarding the quick closing of the mosque after prayer.

Backbiting others is unlawful (haram) in Islamic law, and whoever backbites must repent to Allah.

It is obligatory to forbid those who drink alcohol near the mosque from their evil act, if possible.

It is obligatory to clarify the ruling on foul odors to those responsible for them, and that they harm worshipers and angels. Smokers must remove the smell of smoke from their mouths before entering the mosque or avoid the mosque.

It is not permissible to abandon congregational prayer in the mosque, for its virtue is great.