Some clarification first, there is no 4.0.2 RStudio version, you are confusing this with your R version which is not the same.
micEconCES is available on CRAN for R 4.0.2 so this seems like a connectivity issue, R is not being able to connect to the CRAN repository you have selected, these are some things to try.
- Choose a different CRAN repository, RStudios repository is a good choice (http://cran.rstudio.com/) or you could choose one that is geographically closer to you.
- Disable secure download setting.
- Check if your internet connection has traffic restrictions of some kind, like a firewall, proxy server, etc. This is usually the case when you are at work or school.