Stripe donations 'hang' when made on the onion site

donate.torproject.org has an onion site here:

http://yoaenchicimox2qdc47p36zm3cuclq7s7qxx6kvxqaxjodigfifljqqd.onion

However when attempting to donate via Stripe (i.e. credit card) the donation 'hangs' on the following screen:

The assumption is that Stripe is rejecting the payment due to the lack of an SSL/TLS certificate. We may be able to confirm this from the Stripe dashboard itself, which typically lists rejected payments/API requests.

If that is the case, we'll need TPA's help to purchase and install a certificate for the donate onion.