Can't send XEM from wallet

Guys,

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.

Generally this is not an issue with XEM, but with poloniex.

But: Did you enter that custom message like you are supposed to?