I'm working in an office where several computers are connected via lan, and we can also connect to wifi with our phones. Before I went out for lunch today everything was working fine, but when I came back the computer in my office has no internet connection and my phone won't connect to wifi. Everyone else is the office is having no problems with their computers or their phones. What could have caused this? The error on the computer says default gateway is not available. But why won't my phone connect to the wifi either? Thank you for your help!