Due to the US dollar scarcity which is currently affecting the availability of the greenback in Nigeria, some banks have stopped authorising ATM withdrawal abroad. This means you will no longer use your Naira-denominated card for a cash withdrawal but can still make payment within a certain daily or monthly limit (ranging from $100 to $200) outside the shores of Nigeria to foreign merchants who do not accept Naira for bill settlement; this includes online purchases, hotel or airline booking, and any related fees paid in US dollars.

Diamond Bank SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 13/10/2016
UBN SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 13/10/2016
GTB SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 14/10/2016
Access Bank SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 14/10/2016
Ecobank SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 14/10/2016
S.Chartered SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 14/10/2016
UBA SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 15/10/2016
FBN SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 15/10/2016
Stanbic SUSPENDS INTERNATIONAL ATM WITHDRAWAL FROM 18/10/2016
STANBIC SAYS: From 18 October 2016, you will not be able to use your Naira debit and credit cards for international transactions. Please request for a US Dollar debit or prepaid card for transactions priced in foreign currencies. Call 01 422 2222 for details.

Source: http://www.browsingphones.com/atm-withdrawal-limit-in-nigeria-naira-mastercard-abroad-visa/