“Invalid code”…… WOT!! 
Please wait patiently. I have already asked Wurkkos to check the code. I will get back to you as soon as I have any news. :-)
The code for USA worked for me on Tuesday. I did a copy-paste to avoid error. Maybe it was for limited time?
BTW, it is supposed to arrive today, but sometimes things come a day later out here. Glad the sun is setting earlier so I can use the lights!
Hope you get the code working again.
I ordered mine through Amazon with the code. It should be here today.
Yeh, mine should be arriving arrived today, too.
Just got mine from aliexpress. 
Only 12 days since order, fastest shipping I ever got from aliexpress, usually it’s over 20 days.
:+1:
“The promotional code you entered is not valid” 
….
Could it have been only for existing stock? I don’t recall any “Only 6 in stock, order soon!” or anything, but…
As there are holidays in China this week I don't expect any feedback from Wurkkos before beginning of next week.
I'm confident that Wurkkos will find a way to extend the groupbuy period by a couple of days after September 15, 2019.
Ah, well. Guess I can’t claim that this will be an impulse buy. LOL
In the meantime, perhaps a torch with the three primary colors, to
Dial in each, to create a customized color light.
Let the creative artist in you light up the sky?
Idle thoughts of a patient wurkkos 30 wannabe buyer, aging by the moment….
Anyone knows who makes battery?
Wurkkos just sent me a new code for Amazon US customers, see updated OP.
Cheers,
Thomas
I tried the new code RBCIC36C using the amazon link provided in the original post and it did not work- got the message “The promotional code you entered is not valid.”
Hi it will valid starts from 2019-9-16 06:00PDT
thank you
New code worked for Amazon US. Thomas, Thank you for this deal!, DJ
Yep, all good now. Thanks!
Thank you for your kind feedback, donj + jmoots. Glad to see it works. :-)
FYI: AFAIK, the codes seem to have become invalid and AliExpress is out of stock. I will ask Wurkkos for new discount codes after CND, i.e. as of October 8, 2019.
I hope for more amazon codes.