Long ago I attended a workshop about encryption. Nothing too deep, just basics. One thing the teacher mentioned was that it's very important for encryption devices to have the same time setting. They use it as a part of their handshaking. If time differs too much, they will not connect despite all the other parameters being correct.
Now I know that the encryption devices we use (government manufactured devices for military encryption) use time this way. More than a minute off and they fail to connect.
Does this also apply for ordinary Wifi-routers that you buy at your local retailer?