As far as I understand no deposits or withdrawals from Poloniex are possible for anyone at the moment.  This is indeed frustrating, and we should keep on bugging Poloniex to fix this.

Poloniex states:
"   BTM is currently under maintenance or experiencing wallet/network issues. Deposits and withdrawals will remain disabled until a solution is found, which may require an update from the BTM team. Any updates must be tested and audited before enabling."

There has not been any wallet/network issues for a long time now.  There was a bout of "selfish mining" by some powerful Scrypt mining syndicate where blocks were getting orphaned constantly. But, this not the case any longer and hasn't been happening for many months already, so there really is no reason for deposits and withdrawals to be disabled.