Internet light keeps flashing green, how to resolve this?

Hi ​@Munka Lu and welcome to our KPN Community. I'm not sure which modem you’re using, but if it's the Experia Box V10 for example, a green blinking light means internet is working and data is being transferred. 

Why have you restarted your modem? Is it because you don't have an internet connection?
If that is the case, I'd advise you to walk through or steps for solving internet issues. The page is in Dutch, but most web browsers have the option to translate pages these days, so hopefully these steps help! 

If not, do let me know. 🙂