I reverted to the previous version 1712 (for ubuntu 16) which works.
It seems the new debian 9 package does not refer/link to the right ssl source library
sudo rstudio-server verify-installation
/usr/lib/rstudio-server/bin/rserver: error while loading shared libraries: libssl.so.1.0.2: cannot open shared object file: No such file or directory
The problem is that Ubuntu 16.04 is no longer supported both by Ubuntu and by RStudio. I see four possibilities in descending order of desirability:
Upgrade your operating system to a recent version, e.g. Ubuntu 20.04.
Stick with the last version of RStudio Server supported on Ubuntu 16.04.
Compile RStudio Server from source.
Find backports of libraries needed to run RStudio Server as compiled for some other OS. Debian 9 is a good starting point since that is also quite old. But note that Debian 11 was recently released and hence you won't get builds for current RStudio Server for Debian 9 for long.
Thanks, this is indeed the best case scenario. Unfortunately I have no control on the OS version (University ITs) which is my main issue here. I Will stick to the current RStudio until I get the server upgraded.