When I turn on tethering on my mobile, my phone stops having access to internet

I have recently changed carriers and never had this problem before. I havent changed anything yet but the new carrier claims I should be able to use both (1) pc connected over wifi to hotspot on my phone, 2)my phone as usual). But as soon as I enable 'wifi hotspot' on my Samsung Note 10, newest Android, all of a sudden I cant get email/notifications/data on my phone, until I disconnect. Then everything arrives.