Unable to verify domain – received a 404 status code from your server

Hi

I’m trying to setup Apple Pay via Stripe and getting a 404 – File or directory not found with the apple-developer-merchantid-domain-association file.

My log reports
====Start Log====
Error: Unable to verify domain – We attempted to retrieve the file at https://MYDOMAIN.COM/.well-known/apple-developer-merchantid-domain-association, but received a 404 status code from your server. Please check that the file is hosted correctly. Note that our servers most likely send different HTTP headers than your browser; you should check your logs to see why the request failed. For more information, see https://stripe.com/docs/stripe-js/elements/payment-request-button#verifying-your-domain-with-apple-pay.
====End Log====

I am using IIS, I don’t think it is an access problem because if I add an extension to the apple-developer-merchantid-domain-association file e.g. txt. It will load correctly.

Also when I try to add the domain via Stripe at https://dashboard.stripe.com/account/apple_pay I get the following message

We attempted to retrieve the file at https://MYDOMAIN.COM/.well-known/apple-developer-merchantid-domain-association, but received a 404 status code from your server. Please check that the file is hosted correctly. Note that our servers most likely send different HTTP headers than your browser; you should check your logs to see why the request failed. For more information, see https://stripe.com/docs/stripe-js/elements/payment-request-button#verifying-your-domain-with-apple-pay.

Any suggestions?