Oracle DB not generating AWR Sysaux tablespace is almost full . Could this be the reason AWR snapshot is not generated ? Although I do have the AutoExtend ON for SYSAUX tablespace.
If sysaux hasn't reached it's max physical growth limit, then it is not likely the reason AWR isn't working. AWR can be disabled a number of ways, for good reason. See this link for details:

http://www.dba-oracle.com/t_awr_remove_disable.htm

https://grepora.com/2019/06/05/oracle-disable-awr-and-prevent-to-violate-diagnostic-tuning/#:~:text=Disable%20AWR%20with%20Oracle%20provided%20script&amp;text=To%20install%2C%20run%20the%20package,disable%20the%20AWR%20related%20advisors.


If someone disabled it, you should confirm the reason why before turning it back on. It is an extra cost feature that many systems are not licensed for.