First: we've been using Document Seller on this client's Joomla site for years. We LOVE LOVE LOVE you.
A customer emailed us yesterday saying that she'd tried a number of times and not been able to purchase a document. Then today she was able to successfully purchase the document. I verified that she had tried multiple times over several days. There is only 1 failed order for her logged in our orders listing. Looking back over the last few months, I do notice that sales are down a bit, and there are about 3 or 4 other failed orders from customers. (We have usually 3-4 sales per day... but there are days where there is nothing, others where there are more, so hard to tell. I do see several spells where there are no sales, failed or otherwise for a few days -- and one of those days IS a day she said she tried...)
I'm attaching a screenshot the customer sent. Client was on a Windows 8.1 machine using a Chrome browser. Website is using Joomla! 3.4.1 Stable [ Ember ] 21-March-2015 20:30 GMT with Document Seller version 3.5. So...we've done routine updates to the site. I'm wondering where I should even START to trouble-shoot this.
Clearly, it works some of the time as we're still getting sales. This particular client got multiple fails and a success on the same machine with the same settings.
Going back through the history, I see periodic problems from last October forward. (Maybe one every day or two...) Generally an order shows as not paid, then there is a second order that shows as paid. While I understand this can happen legitimately, I don't see any before October. Since then, they seem to be increasing in frequency. If there are any others that aren't logging, I won't know that. Sadly, not all of our customers tell me when things go wrong. (Most don't...)
Thoughts?