@andreamike If the IPv4 address starts with 101..., then I presume it should be reachable from the Internet. So if you setup port forwarding on the Sky router to forward UDP port 1194 to the internal...

@alexet Hi, The answer is easy, but unpleasant. Your mobile/cellular provider has placed a CG-NAT (basically another NAT router) between your router and the actual Internet. (to save precious public...

@andreamike Are you able to log into the Sky router's configuration webpage? If yes, can you check if the Sky router still obtains a public IPv4 address from your ISP and if it also has a port...

@Surya1970 Hi, What are the model numbers of both devices? How far in the setup process have you gotten? When you try to setup the TP-Link range extender can you find the SSID (Wi-Fi name) of the...

@Ryoko_L Defective cables can certainly cause weird intermittent problems. But why the problems only showed up whenever that notebook was connected via wireless in unclear.

@Ryoko_L Yes, if another Wi-Fi router exhibits the exact same problem, then there must be something else not right. Can you check if the system logs of the routers contain any useful information...