I think i have done it . There was some problem inside file nextor.properties.I have inside this file for my version cas:
cas.javascript.file=/themes/nextor/js/cas.js < - according to documnetation
but sould be:
cas.standard.js.file=/themes/nextor/js/cas.js
But there are another problem that after authtentication and logout from nextor ( nextcloud) service if i would like to log again cas use css and js from customzation it doesnt use customized *.htm files (it use only css i js files ). Any advaises ?