Cant find USPS by Stamps Carrier when Adding Carrier

Hi,  Can someone please help me? 

I wanted to add a USPS by Stamps carrier on our ShipStation account. I tried the below, however I cannot see "United States Postal Service by Stamps.com" on the tile list the same as the one on the tutorial. I tried to reach out to ShipStation chat support but the guy said I need to contact Stamps about this. I think what he said to me doesn't make sense why will I ask Stamps if the problem is in ShipStation and I haven't started the connection yet because USPS by Stamps is not on the tile list in the first place. I am currently lost, can someone provide insights or clarity? Thank you!

Connect a Stamps.com account to ShipStation
https://help.shipstation.com/hc/en-us/articles/360026142111-Stamps-com#UUID-fa8694f0-0acf-f556-fc87-c993d916ed95_UUID-0df91fbf-70ea-e8e3-cd13-bf903e4a6265