I got an error trying to buy something at Staples. Worked in internet explorer.
I cannot paste the error message here.
Here is the error message.
We are unable to process your request at this time. Please close this window and try again.
Don't know why it does that - never used Staples - maybe you can try to change the user agent with the one of internet explorer the next time.
Other browsers get the error too? Do you have adblocker on?