Plotly Intallations problems on Rstudio on MAC

Hello!
I´m new.
I have Rstudio Version 1.4.1106 for MAC

Hello! I´m new. I have Rstudio Version 1.4.1106 for MAC.
I’m trying to install Plotly, but Rstudio send me this message:

"Warning in install.packages :
unable to access index for repository https://cran.rstudio.com/src/contrib:
cannot open URL ‘https://cran.rstudio.com/src/contrib/PACKAGES
Warning in install.packages :
package ‘Plotly’ is not available for this version of R

A version of this package for your version of R might be available elsewhere,
see the ideas at
https://cran.r-project.org/doc/manuals/r-patched/R-admin.html#Installing-packages
Warning in install.packages :
Perhaps you meant ‘plotly’ ?"

I will be grateful with your help!