please check below solution,maybe useful for you ,
You have to use web page from server with application U2000. Normally is HTTPS://ipADRESSofSERVER/cau . On this page please use IE version 8-11 32bit with all security upgrades.
Like first please, check your set in INTERNET OPTIONS, and if you can add U2000 IP adress into trusted servers. Chose Internet options / 2nd tab named SECURITY / chose Trusted Sites / use button SITES / add your IP of U2000 server in format https://IPadressOfServer .
Now jump into web pages and tick "I have read the instructions mentioned above and executed thesteps before launching the setup.", and input code form picture.
Now is necessary to load from point 5 certificate import toll , and run it (save to desktop, unpack and use). This tool will install necessary certificate, and allow use JAVA for load client U2000. If you have still some security problem, please check all set from help from point 5, where is list of all possible problem, and how to fix it.
If you have your server in trusted sites, and your certificate is migrated into your system, will normally possible to use CAU function, and load client from U2000 server.