What are the excuses that permit a Muslim to miss congregational prayer?

Congregational prayer is a noble act of worship that should not be taken lightly. The majority of jurists do not obligate congregational prayer in the mosque. If a congregation is found at home or elsewhere, it is permissible for you to pray with them, but praying in the mosque is preferable. However, if you know that you will not find a congregation [elsewhere], then you are primarily obligated to pray with the mosque congregation.

A cleansing shower is not an excuse for missing congregational prayer, unless you have excessive sweat with an odor that bothers the worshippers. As for missing the congregation due to ablution, you should prepare yourself with sufficient time. And for one who misses the congregation after performing a proper ablution, Allah will grant him a reward similar to that of one who prayed and attended it.

If your illness weakens your walking to the extent that you cannot catch the congregation, then you are not obligated to go. And if walking to the mosque usually causes you fatigue, then the obligation of congregational prayer in the mosque is lifted from you. It is permissible to combine prayers in case of illness if it becomes difficult for the sick person to perform each prayer at its appointed time, and likewise due to hardship and difficulty according to some scholars.