In my case, our company upgraded intermediate certificates to SHA256, unfortunately at the same time they disabled HTML5 client (probably for compatibility reasons related to SHA256), so Citrix was suddenly completely broken in Linux. The reason why this may appear just now more frequently is that SHA-1 are not very secure so logically servers migrate to new SHA-2 certificates, which have poor support in slightly older ICA clients and this produces this misleading error.
It might not solve all the occurrences of this error, but at least some of them. I found out that newer version of icaclient (13.3) supports SHA-2 keys, so upgrading of icaclient solved the problem. The message is unfortunately very misleading, it is probably re-used for multiple different situations. Then I found out that the problem in my case was that my icaclient did not support SHA256 certificates (it did not support any SHA-2 certificates).
Citrix and Microsoft might change cer-tificates and CAs in the future, but will always use CAs that are part of the standard Windows Trusted Publisher list. If you're supporting a secure gateway / access gateway solution for external clients / home working, you'll. The Cloud Connector must trust the certification authority (CA) used by Citrix Cloud SSL/TLS certifi-cates and by Microsoft Azure Service Bus SSL/TLS certificates. Google advised a lot of things that did not help, the same error message still persisted. common causes for 'There is no Citrix SSL server configured on the specified address.'. I have installed them correctly into /opt/Citrix/ICAClient/keystore/cacerts, then I did the rehash with "c_rehash /opt/Citrix/ICAClient/keystore/cacerts", I have also updated directories /etc/ssl/certs/ and /usr/share/ca-certificates/mozilla/ and run update-ca-certificates.
Like javy666, regardless what I did with certificates, I was still getting this error. I had similar problem (with icaclient 13.0) under Ubuntu 14.04 LTS.