A workaround below, if
sudo apt-get install apt-transport-https
is not letting you install apt-transport-https
.
#Do not use apt-get
#Download apt-transport-https .deb package directly from Debian repositories
pi@piaware:~$ sudo wget http://ftp.at.debian.org/debian/pool/main/a/apt/apt-transport-https_1.0.9.8.4_armhf.deb
--2018-02-27 13:24:42-- http://ftp.at.debian.org/debian/pool/main/a/apt/apt-transport-https_1.0.9.8.4_armhf.deb
Resolving ftp.at.debian.org (ftp.at.debian.org)... 2001:858:2:1::10, 213.129.232.18
-----------
2018-02-27 13:24:43 (171 KB/s) - ‘apt-transport-https_1.0.9.8.4_armhf.deb’ saved [135040/135040]
#Check if the file downloaded successfully
pi@piaware:~$ ls
apt-transport-https_1.0.9.8.4_armhf.deb
#Install the downloaded .deb package
pi@piaware:~$ sudo dpkg -i apt-transport-https_1.0.9.8.4_armhf.deb
(Reading database ... 32611 files and directories currently installed.)
Preparing to unpack apt-transport-https_1.0.9.8.4_armhf.deb ...
Unpacking apt-transport-https (1.0.9.8.4) over (1.0.9.8.4) ...
Setting up apt-transport-https (1.0.9.8.4) ...