Could Not Connect to Amazon RDS Oracle Database From Car Dealer WiFi

I am trying to connect to my Oracle database on Amazon RDS at a car dealer while my car is in service. My laptop is connecting to the public WiFi. When I try to connect to the Oracle server, I got "Error Message = IO Error: The Network Adapter could not establish the connection".

I realized the issue is caused by the new ip address not included Amazon Security Group inbound rules. I find my ip address. Then I log onto Amazon AWS console and find the security group associated with the DB instance. After I add a inbound rule 64.188.5.xxx/32, I am able to connect to the DB immediately.