Reason - Due to unconfirmed inputs.
Can someone please explain what this means and could the sender do this intentionally. In other words to scam someone.
If there are three addressess A
, B
and C
and someone sends a transaction tx1
from A
-> B
and another one tx2
from B
-> C
that spends the exact same coins (tx2 input is tx1 output) then tx2
cannot be confirmed until tx1
is confirmed.
Yes someone could trick you to accept an unconfirmed transaction as final and then send the same coins elsewhere (with a higher fee). That’s why you should not consider transactions final unless they are confirmed with at least a few confirmations (6 used to berecommended)