What wireless mode are you using on the TP-Link AC 175? You may need to try a different one. Even if you are using, say, 'g, n and ac mixed' the WAP54G may not be working correctly with that. Try, if available, 'g only.'
Does the TP-Link AC 175 need to be set to allow a wireless bridge to be connected? Or need the MAC Address of the wireless bridge?
Does the TP-Link AC 175 need to be set to allow a wireless bridge to be connected? Or need the MAC Address of the wireless bridge?