this is usually due to the female flower being pollinated/fertilizer by the male flower. remove the male flower, the one without the baby cucumber behind it. then all the emale flowers will develop without the bitterness.

if they are all female plants then I dont know.

welcome to GoY too.

thanks i will try this

In older varieties that are supposed to be pollinated, waiting too long to harvest, and drought, are the two most common causes of bitterness.