All of a sudden we started to get the below message when a customer tries to checkout. any ideas? We contacted authorize.net and they said: Have your web developer change the endpoints to one of the following.
Well I checked and it is pointing to :
Your registration was failure
[curl] 6: Could not resolve host: secure2.authorize.net; Name or service not known [url] https://secure2.authorize.net/gateway/transact.dll
Back to your question, from what I see, it might happens because your server has something blocks the request to
and it causes the issue. Try to contact your hosting provider, asking them to check to see if they block, if they do, remove it and it should work OK