Thank you for the additional information.
Check if your Meraki Go wireless network is running on Bridge-Mode, go to Settings -> Advanced settings -> Wireless address translation mode
If you are using IPv6 make sure Wireless IPv6 bridging under "Site-wide wireless settings" is enabled.
Other steps you might want to try:
- reboot your whole network
- check if you can get a connection without using PoE
- check if your network-devices are running on the latest firmware