Chanukah* after Yom Kippur
The Mogen
Avraham & Baer Heiteiv quote from the Mahril, not to fast
or say Tachanun ,between Yom Kippur and Succhos, because it is
a mini YomTov.
It commemorates the Chanukas Hamizbeiach
in the times of Shlomo Hamelech.
The
Levush writes the Yom Tov is, Hashem doesn’t count the
sins till the first day Succhos.
*Now you understand the
sod (secret) of " Git Kvittel"