can't load library 'libz.so.1'

Hi All, I am running ASUSWRT-Merlin 380.65_4 on my RT-ACC66U and I am getting this error and don´t know how to get rid of it. admin@RT-AC66U:/tmp/opt/bin# ssh-keygen ssh-keygen: can't load library 'libz.so.1' admin@RT-AC66U:/# sshd sshd: can't load library 'libz.so.1' the file exists as...