It took two hours to withdraw from Poloniex last night!!  :-\ Maybe I'l try BTER next time.

Thank you Soniq, yes I was using my BTSX name.
Thank you Troglodactyl, that worked. Yes I was using a memo first, then tried without the memo, I had a withdrawal confirmation email from Poloniex, however I still haven't received my BTSX into my wallet....

Are you using the memo field?  I got that error once and tried again without a memo and it worked, but I'm not confident if their memo handling is buggy or if the problem was something else and that was a coincidence.  If it works without the memo let me know, we should report the issue to them.

use your registered BTSX name to withdraw, not your BTSX address

Hi, I've just synced and registered my wallet and received 1BTSX from testzcrypto on this forum, however when I try to withdraw my BTSX from Poloniex a message appears 'Invalid Payment ID'.
Could anyone help or explain what I could be doing wrong?
OR how can I withdraw BTSX from any Exchange?