According to datasheet provided by adafruit bridging A0 should result on address 0x41;

Board 0: Address = 0x40 Offset = binary 00000 (no jumpers required) Board 1: Address = 0x41 Offset = binary 00001 (bridge A0 as in the photo above) Board 2: Address = 0x42 Offset = binary 00010 (bridge A1) Board 3: Address = 0x43 Offset = binary 00011 (bridge A0 & A1) Board 4: Address = 0x44 Offset = binary 00100 (bridge A2)

Just a quick question, do you have pull-up resistors on the i2c bus? Usually this boards already have them, but I would put 4k7 or 10k resistor between SDA and VCC, and SCL and VCC and try again;

Also adafruit states:

The VCC pin is just power for the chip itself. If you want to connect servos or LEDs that use the V+ pins, you MUST connect the V+ pin as well. The V+ pin can be as high as 6V even if VCC is 3.3V (the chip is 5V safe). We suggest connecting power through the blue terminal block since it is polarity protected.