Unfortunantely we have some Wifi connection issues and after trying all recommandations here, the issue is still the same. Clients lossing connection from time to time and cannot reconnect to the router. Only workaround reboot router. After further review it appears our router firmware was since we got it 2 years ago never updated. Since over one week I try to get hold of someone at TPG to help no chance to get one. Either by phone or chat.
Hope a Moderator can help here. As customer service cannot be contacted otherwise it looks like.