In order to fix this issue you have to change the MTU size for your network card. Do that by following the guide below:
- Open System Preferences.
- Click the Network icon.
- Double click ”Ethernet (built in)” or choose ”Ethernet” from the Show drop-down menu.
- Click the ”Ethernet tab”.
- Under "Maximum Packet Size (MTU) choose Custom and enter 1400 in the box.
- Click "Apply now".