Did you just create a NanoWallet?
It seems that Bittrex has established restrictions not to send remittance to NanoWallet which has never sent external remittance.
This is not a specification of NEM. Bittrex has set such restrictions.
In order to solve this problem, it is good to do it once from NanoWallet, so it is necessary to do remittance processing to the outside.
On technical terms, NanoWallet, which has never remitted money, has no public key issued. By transferring money from NanoWallet, a public key is generated.
thnaks