@miru miro :
It seems like the error message is indicating that there is an issue accessing the package repository at https://cloud.r-project.org/src/contrib/. This could be due to various reasons, such as network connectivity issues or the repository being down.
You can try specifying a different repository by using the repos argument in the
install.packages function. For example, you can try using the following command to install RMySQL from the CRAN repository:
install.packages("RMySQL", repos = "http://cran.us.r-project.org")
This should download and install the package from a different repository. If this still does not work, you may need to investigate further into the network connectivity issues or try installing the package manually.