Hello,
In your callstack I can see that you have an override for the HikaShop order class.
Would it be possible to know what your override is doing ?
And would it be possible to have the line "1921" of the file with the error.
When I look at the source of HikaMarket 4.1.1 ; the error is not logical because just above the variable $order is read and can't be empty.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.