Hi @radhika_k ,
Assuming you must be installed AEM SP 6.5.5, in that case please navigate
https://<HOST>:<PORT>/libs/granite/core/content/login.html
login and then navigate to /crx/de
For more details please read this article [0].
[0]: https://www.techinnovia.com/how-to-easily-access-crx-de-after-aem-6-5-5-upgrade-sp5/
Hope that helps!
Regards,
Santosh