I faced this issue of UBUNTU 18.04.
I saw other solution on the internet, but they did not work for me.
I hope this blog helps you.
Citrix complains about “User Trust rsa certification authority” permission does not exists.
The /etc/ssl/certs folder has a permission file with exact same name USERTrust_RSA_Certification_Authority.pem .
So, I copied this certificate from /etc/ssl/certs to /opt/Citrix/ICAClient/keystore/cacerts.
the entire command is
sudo cp /etc/ssl/certs/USERTrust_RSA_Certification_Authority.pem /opt/Citrix/ICAClient/keystore/cacerts
if the above does not work. then you can create a symlink to all the certificates present in Mozilla folder. You really do not need all. But, it it easier.
sudo ln -s /usr/share/ca-certificates/mozilla/* /opt/Citrix/ICAClient/keystore/cacerts
I really hope this helps.
Because, this error is not fun at all.