Which birth day are you filling?
Ted here from Shopify, thanks for reaching out to us!
How far along are you with the set up of your store? I was just taking a look there and we normally do not require date of birth information when you first open an account. Instead, we only ask for an name, address and phone number as shown in this screenshot for example. Are you trying to set up a payment gateway account? If so, could you tell me the name of the gateway you are trying to connect with? If not, could you show me an example of where you are trying to confirm your date of birth? If you are able to send a screenshot of this information, that would help greatly as well!
How are you finding Shopify so far? Do you know the type of business you would like to set up? If there’s anything else I can help you with please let me know, I'm happy to help!
Thanks for reaching out to us and for the example! Instead of entering 19870713, could you try entering 1987-07-13 as shown in this example and let me know if this works for you?