Use the WalletKit dashboard to set Allowed Origin on the Settings page

You must configure a list of allowed origins in the WalletKit dashboard for CORS to work. This is a security measure to prevent malicious websites from using your Project ID. Head over to the Settings page in the WalletKit dashboard. Under the Allowed Origin section, add a list of comma separated origins that you want to allow. For example, if you want to allow https://example.com and https://example.org, you would enter: 
https://example.com, https://example.org