Why did the prohibition amendment fail after its adoption in 1919?

The correct answer is: "the two main reasons were: llegal liquor-related crimes and lack of popular support".

The 18th Amendment to the US Constitution was ratified in 1917, and it reflected the success of the temperance movement that had been very active during the previous decades. This amendment banned the production, sale and consumption of alcoholic beverages, acknowledging the negative consequences that consuming alcohol caused in human health and its role as a source of social issues such as poverty.

The 18th Amendment was repealed by the 21st Amendment, ratified in 1933. The main reason was the organized crime groups were enriching themselves smuggling with alcoholic beverages, and many related crimes started to harm the US society. Moreover, the population did not support the prohibition and they did not contribute at all to its proper functioning.