Nexus 7 keeps disconnecting from wi-fi My Nexus 7(android 6.0.1) constanly drops wi-fi connection(connects and disconnects immediately), presumably due to bad connection, while Nexus 5x lying next to it is staying connected just fine.
I got logs using adb and i think the cuprit is

04-30 11:15:38.013   594  7142 D NetworkMonitor/NetworkAgentInfo [WIFI () - 133]: Forcing reevaluation for UID 10022
04-30 11:15:38.018   594  7142 D NetworkMonitor/NetworkAgentInfo [WIFI () - 133]: Probably not a portal: exception java.net.UnknownHostException: Unable to resolve host &quot;connectivitycheck.gstatic.com&quot;: No address associated with hostname
04-30 11:15:38.019   594   663 D ConnectivityService: NetworkAgentInfo [WIFI () - 133] validation failed
04-30 11:15:38.019   594   663 D ConnectivityService: notifyType CAP_CHANGED for NetworkAgentInfo [WIFI () - 133]
04-30 11:15:38.027   594   663 D ConnectivityService: sendStickyBroadcast: action=android.net.conn.INET_CONDITION_ACTION
04-30 11:15:38.079   594   663 D ConnectivityService: NetworkAgentInfo [WIFI () - 133] EVENT_NETWORK_INFO_CHANGED, going from CONNECTED to DISCONNECTED

I've checked from PC connectivitycheck.gstatic.com can be reached from my network, both dnslookup and ping work on it
There is no option in wi-fi setting to disable avoid bad wi-fi connection.
What can be done?
EDIT:
Rebooting router and rebooting device did not help. I've also checked the router logs and settings, the device is not blacklisted, and router logs look just fine consistant with the behaviour - device connected, some negotiations, device disconnected.
As i didn't find any solution neither on the internet nor here, i've desided to just flash my tablet using image from google, it helped. 
Edit: Factory images for all nexus devices can be found  at this page, it contains simple to follow instructions on how to flash your device as well as images. Take care though failure during flash can brick your device