Some URLs won't load over WLAN but load over LAN

Hi,

I've got the same Problem on 3 different Locations (2 companies): some URLs just won't load over the wireless Network while they load just fin over LAN.

for example: https://d3ui957tjb5bqd.cloudfront.net/js/common.js?66a3966

Could also be a .css or a webfont or anything like that.

The WLAN is bridged to an internal LAN interface, Clients aquire their IP addresses over DHCP. Everything else is working just fine.

I tried

- excluding a client from Webprotection.

- allow all from this client to the internet

Nothing works. As a result i get: The connection over https could not be established.

Any ideas?

Thank you very much,

Michael