وَيُسْتَحَبُّ أَنْ يَكُونَ الْمُؤَذِّنُ صَالِحًا عَالِمًا بِالسُّنَّةِ وَأَوْقَاتِ الصَّلَاةِ، وَعَلَى وُضُوءٍ، مُسْتَقْبِلَ الْقِبْلَةِ
The preferred caller is upright in conduct, knows the Sunnah and prayer times, is in Wudu, and faces the Qiblah. These are qualities of the optimal Sunnah performance; they should not all be mislabeled as conditions without which every Adhan is invalid.