I am testing Visa Checkout Button and is getting the below error using Chrome version 63. No problem when using Chrome version 62, Firefox, Microsoft Edge or Opera. Attached is the print screen.
The SSL certificate used to load resources from https://sandbox-assets.secure.checkout.visa.com will be distrusted in M70. Once distrusted, users will be prevented from loading these resources. See https://g.co/chrome/symantecpkicerts for more information.
Thank you for posting your question. We will take a look into this for you and get back to you soon.
Visa Developer Team
Thanks for your patience, as I began digging deeper into your question, the issue you are seeing is part of Chrome's drive to "“reduce, and [..] remove, trust in Symantec’s infrastructure in order to uphold users’ security and privacy when browsing the web.”: https://security.googleblog.com/2017/09/chromes-plan-to-distrust-symantec.html." The change listed in the error messages apply to Chrome v70 and it will be implemented by the week of October 23, 2018.
In the future, Visa Checkout has plans to update Symantec issued certificates, which will resolve the error message as well.