When you say "i am not using simplified chinese on my system." does that mean your OS is NOT set to simplified Chinese or that you don't want to use it? If you go into the Creative Cloud app, click the three vertical dots on the top-right, then go into Preferences>Creative Cloud>App, what is the language there? Both your OS and the CC app must be set to Simplified Chinese.
I'm not sure why support told you to post on the forums. I would call them back if this is the last day of your trial. I know the US has a 7 day trial, 3 days doesn't seem like enough at all.
You could try signing out, uninstalling the CC app, and reinstalling to see if that helps.
The error message does specify that your browser also needs to be in Simplified Chinese. I'm not sure why that is, but it's worth changing to see if that helps.
i tried to contact the cs via live chat, she asked if I bought it, i said no.
because i am not a customer yet, so she asked me to go to the forum, and cut the line immeidately, very rude
anyway, i tried your mentioned way already, no use
Sorry for this negative experience. Did you ever get to run the trial for After Effects? Hope all is well. Please let us know what happened.