Hi @Danh_Le
You may have skipped over this section:
MongoDB 4.2 Community Edition supports the following 64-bit Ubuntu LTS (long-term support) releases on x86_64 architecture:
- 18.04 LTS (“Bionic”)
- 16.04 LTS (“Xenial”)
See the commenst from @Stennie_X Ubuntu 20.04 support - #2 by Stennie_X
Mongodb error in Ubuntu 20.04 - #3 by Stennie_X