Questions regarding id’s

Hello, i have just turned 21 and a current resident in Arizona. So far whenever I’ve tried to get anything from any gas station I’ve been turned down for attempting to buy a couple beers because I have a vertical id. I just applied for my travel id today but I don’t think there is anything against using a vertical id to purchase alcohol if you are of age for at least 30 days after your birthday. I’m super confused on why this is happening. Are places just being super strict or am I in the wrong?