Hello and welcome to the forum 
You may have a missing digit when specifying the version. Try rasa-x==0.42.3 (newest version - in this case no need to specify it, just use rasa-x).
@kaer12 Hello and welcome to the forum!
Can you please share the rasa --version, while activating your environment?
@kaer12 Hello, I guess you solve this? can I request when you got time, do share the complete installation step for installing rasa x and even share the rasa --version after installing the rasa x. It will help a lot to other users, many thank in advance
okk，thanks，I’m actually still working on this problem. If ok I will share you. @nik202
@kaer12 share the issue you facing, lets solve together