Please use 885-151G from Ubiquiti as a sub for this product. It is 1Amp but will work fine as a replacement for the GP-A240-050 which aare hard to find now.
Ubiquiti 24V .5 Amp Power Supply...
The TS-5-POE 5-Port TOUGHSwitch by Ubiquiti Networks features five (5) Gigabit PoE ports, 24V configurable passive Power over Ethernet (PoE), 60 Watts total power, TOUGHSwitch PoE configuration...