Downloading https://cloud.r-project.org/bin/linux/debian/jessie-cran3/InRelease...
Downloading https://cloud.r-project.org/bin/linux/debian/jessie-cran3/Release...
Downloading https://cloud.r-project.org/bin/linux/debian/jessie-cran3/Release.gpg...
gpgv:  DSA key ID 381BA480
gpgv: Good signature from "Johannes Ranke (CRAN Debian archive) <jranke@uni-bremen.de>"

Mirror [mirror14]: https://cloud.r-project.org/bin/linux/debian/ ./jessie-cran3/ successfully added.
You can run 'aptly mirror update mirror14' to download repository contents.