It was a slap in the face for Merkel.
Kauder was her closest confidante and he was the one who had the power to rule the members of the CDU party.
After 13 years he was finally voted out of his position
with only 8 votes more in favour of his opponent
(iirc, there were around 250 people voting as a whole).
This outcome was also a result of voting in secret
and not like usual with open hand signs.
Merkel will not resign.
More revolts will have to happen.