Exactly what happened was never stated - it just mysteriously changed over. The best that's known, some time after the Season 1 finale, the Huntik.com website was redirected to the Huntik.it website. Huntik did originate as an Italian cartoon, so doing so would make sense if they didn't want to maintain 2 websites. Even as things stand, the franchise isn't exactly keeping up with 1 website now.
Maybe yes, maybe no. Keeping a website running costs money, and if a series is on hold for a number of years, keeping two sites running may not result in enough return for their expenditures. The English version was also a lot more complex than the Italian version, and that means even more to keep it running. However, at the end of the day, it was their choice, and they didn't publicize their reasons for doing so.