The fatwa explains that if someone enters the mosque and the imam has already started the obligatory prayer, meaning the congregation has begun, then it is makrooh to pray Tahiyyatul Masjid. It is also makrooh for a person entering Masjid al-Haram to leave the tawaf and pray Tahiyyatul Masjid, because tawaf is the greeting of that sacred mosque. The ruling also states that praying Tahiyyatul Masjid during generally disliked times is not makrooh. Islamic scholars clearly mention these two specific cases where the prayer becomes disliked.