Whatsapp Call Connecting

Hi Guys , i just upgrade from iphone 7 to iphone Xs Max. i have this whatsapp problems where i can't make a call at all and only stated "connecting" . and more weirdly i did tried whatsapp call 3 days in a row and its only available from 1am till 7am. I don't think i did setting anything on this new phone. anyone can help me solve this matter please.