Answer: In this case, it is likely that the issue was caused by the individual looking at the wrong Ethereum address. This could be due to a fake account messaging the individual, pretending to be the intended recipient, and providing the wrong address. To avoid this issue in the future, it is important to double check the address before sending any funds and to be aware of potential scams. Additionally, it is best to communicate via direct message (DM) when dealing with sensitive information such as Ethereum addresses.