I've tried buying a steam gift with keys through this site for the past 5 hours. Initially the problem was that I was told I didn't have the required items, this is understandable as I had just acquired them but for at least 4 hours now clicking purchase eventually gives me the message
Could not retrieve your backpack information, you may have set the permission as private, or Steam is busy.
I've tried re-entering my trade link, attempting the transaction on a different browser and I've tripled checked my inventory is public and still no avail.
Am I doing something wrong here or should I just wait longer?