Your demo account may have expired, try opening a new one.
When the new order window is greyed out, means that either you are not logged in with a valid account, or your haven't enabled trading for the
Make sure you have enabled the specific symbol you are trying to trade in MT4/5 >> View >> Symbols.
The last one seems more probable, I always forget that.
why the new order option is grade out in my demo account
Check the reasons above.
Please enable the necessary setting in your browser, otherwise you will not be able to log in.