Wi-Fi could not be joined, error -3902 Sudently I can't connect to the wify at home anymore from my mac (all other devices are ok).

When trying to connect I get the dialog:

The Wi-Fi network "My_Wifi" could not be joined.

Try moving closer to your wireless router. Alternatively, run Wireless Diagnostics to troubleshoot.


And on the logs from /private/var/log/wifi.log: 

Info: &lt;airportd[51]&gt; Failed to associate to WI-Fi network My_Wifi on interface en0, returned error code -3902
I found that rebooting either the router and or the computer solves the problem. Why it happens I don't know.