Problems installing packages in Rstudio

I must use RStudio and they have not taught me how to use it. I already installed R, Rstudio and RTools, but when I try to install a package I get the following error and it just won't load. Can you help me to see what happens? Thank you.

I am able to replicate this error message by disconnecting myself from the internet, and attempting to install a package.

Thank you very much for your answer.
I tried it and it worked for me.