This is a very weird problem.
I've tested all the steps of the checkout process and it works fine most of the time. By most of the time I mean, in the local environment, it works on Chrome, Safari & Firefox but on a live server such as the staging environment, it works on Chrome & Firefox but not Safari
I tested both my own template as well as the pre-installed examples and got the same results. No luck with Safari on Staging Env.
I've also tested on Safari & Chrome on iPhone & iPad & the same thing happened. Chromes works well but Safari just doesn't want to do its job.
I've tried all the solutions from this question but still no luck.
Here is some of my system info:
Expresso Store: 1.6.4
I don't think that there's any problem with the server though. have you ever experienced this issue? If yes, can you tell me where to start investigate?