unable to download package

[jren]

Hi, I'm very new to R and R studio. I have R studio on my desktop on windows 10 system. I was the only student having trouble downloading packages needed for class, such as tibble, dplyr... My TA wasn't able to solve my problem so HELP!!!!
R version 3.6.0
I uninstalled my R and R studio and reinstalled them again but it still didn't work......

error info in the console:
Warning: unable to access index for repository http://cran.rstudio.com/src/contrib:
cannot open URL 'http://cran.rstudio.com/src/contrib/PACKAGES'
Warning: unable to access index for repository http://cran.rstudio.com/src/contrib:
cannot open URL 'http://cran.rstudio.com/src/contrib/PACKAGES'

install.packages("tibble")
Warning in install.packages :
unable to access index for repository http://cran.rstudio.com/src/contrib:
cannot open URL 'http://cran.rstudio.com/src/contrib/PACKAGES'
Installing package into ‘C:/Users/35132/OneDrive/Documents/R/win-library/3.6’
(as ‘lib’ is unspecified)
Warning in install.packages :
unable to access index for repository http://cran.rstudio.com/src/contrib:
cannot open URL 'http://cran.rstudio.com/src/contrib/PACKAGES'
Warning in install.packages :
package ‘tibble’ is not available (for R version 3.6.0)
Warning in install.packages :
unable to access index for repository http://cran.rstudio.com/bin/windows/contrib/3.6:
cannot open URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/PACKAGES'

I turned off my firewall and antivirus already. I really don't know what else to do. PLS HELP ME!! Thanks in advance.

[cderv]

Do you have internet connectivity on this computer ?
It seems like R does not manage to reach the web and http://cran.rstudio.com

Do you have a proxy to configure ?

[jren]

I do have internet connection. I tried both school wifi and home wifi, but neither works.
Sorry I don't really know about the 2nd question.

[cderv]

can you change your repository to https://cran.rstudio.com ?

In the IDE or with options(repos = c(CRAN = "https://cran.rstudio.com"))
then try

available.packages()

Do you have a result ? If so, internet access is ok.

[jren]

here's a screenshot of my security setting

[jren]

@cderv

available.packages()

this is what I got if I did it right

options(repos = c(CRAN = "https://cran.rstudio.com"))
available.packages()
Warning: unable to access index for repository https://cran.rstudio.com/src/contrib:
cannot open URL 'https://cran.rstudio.com/src/contrib/PACKAGES'
Package Version Priority Depends Imports LinkingTo Suggests Enhances
License License_is_FOSS License_restricts_use OS_type Archs MD5sum
NeedsCompilation File Repository

[cderv]

you really seem to have internet connectivity from R on your PC.
It is really difficult to help on this non R matter from where I am.

[jren]

It's okay. I appreciate your help.