It could be due to several reasons:
1. The wallet address is not copied correctly. There could be a missing letter or number causing the error.
2. Extra spaces before or after the wallet address makes the address invalid. Please check and remove if any.
3. Your wallet elsewhere is not upgraded, hence Hashnest wallet cannot be recognised. This is especially so in the case of LTC and BCH wallet. BCH wallet holders may choose to use legacy address.
4. Network jam. Sometimes the deposit may take longer usual. This is common.
5. In the case of USDT, some customers did not receive the funds despite numerous confirmation. This is because the Omni platform does not relay data on time. Please contact customer support for further assist. Rest assured that your funds are not lost yet.
Most often then not, this is because you did not meet the requirements of your wallet withdrawal. Please check with your wallet provider to ensure your receive your funds on Hashnest timely.