I am using space in my username and when I tried to use CPPAN, it showed following error.
You have spaces in the storage directory path. CPPAN could not work in this directory: 'C:\Users\[USER NAME]\.cppan\storage'
Searching online did not yield any result and gradually found this link (https://github.com/cppan/cppan/blob/6412cba134147c5c8a5da424dd72ea62e779e4b1/doc/faq.md) which shows how to change storage directory path.
All you have to do is open “C:\Users\[USER NAME]\.cppan\cppan.yml” and change the “storage_dir” value to your choice without space and it will work.