Is 855 area code a scam?

No, in North America (USA, Canada, etc.), area code 866 just means it's a toll-free number. There are certainly some scams with toll-free numbers, but the vast majority of toll-free numbers are legitimate. The toll-free codes in North America are 800, 888, 877, 866, 855, and 844, with 833 and 822 reserved for future toll-free use.