How to Fix for ‘Unfortunately, there are no eligible devices associated with this Google account'

Step 1: CHECK/SELECT Android Device Manager at Settings->Security->device administrators.

Step 2: goto Settings>Google>Security>Android Device Manager and UNCHECK Allow Remote lock and erase.

Step 3: Goto Settings->Apps->All->Google Play Services-> storage>manage space>clear all data. This action does not clear your personal data.

Step 4: Goto back Settings>Google>Security>Android Device Manager and CHECK Allow Remote lock and erase.

Step 5: Restart your device.

Step 6: wait for few minutes and goto https://www.google.com/android... and your nexus device should be seen now. if not, make sure to CHECK/SELECT your nexus device in https://play.google.com/settin... 'show in menu'