I also posted this on the NEM forum.
I've tried twice to send XEM to Polo, but the transactions remain on pending and after one hour they time out.
What can I do about this?
I have the latest client (of course), blockchain is synched, my accounts are added correctly.
are you adding the unique message?
Yes, I do. The transaction never gets picked up by the blockchain.
Also, have you contacted Poloniex?
The transaction never leaves my wallet, so there isn't anything Poloniex can do about that.