Q: MacBook Air 2013 suddenly cannot get internet with home Wi-Fi (all others good)

My MacBook Air (2013, 10.9.5, U.S. issue, currently in SE Asia) stopped connecting to the home wireless router via Wi-Fi.  Before Wednesday there were no problems. I shut off my computer Wednesday evening at home, did not take it anywhere else, turned it back on Wednesday night at home and there was no connection (still the same 3 days later).

Connection:

The signal is strong, full bars of strength as listed, password is correct.

I had been using it for roughly 6 weeks at this location with this computer and that router (router did not change)

Router had not been reset, turned off, damaged, etc. before the problem occurred.

Router is standard issue by internet company.

I updated to 10.9.5 probably 2 weeks before, no problems.

The other people have experienced no problems (MacBook Pro and iPad Mini).  My iPhone still connects to WiFi.

Other people have been using same router with same devices for 6 weeks also.

When I connect directly via Thunderbolt Bridge, I have internet.

I have connected the Air to Wi-Fi networks outside home without problems.

The Problem:

I am not connected to the internet at all.  No delays, no trying, only zero connection.  “Page not found because you are not connected to the internet,” etc.

When I connect to the Wi-Fi, I get a checkmark next to the Wi-Fi name, but the menu at the top has an exclamation point, with “Alert: No Internet Connection” in the same menu.  This happens after around 10 seconds of trying.

There are no default DNS servers when I click “advanced.”

Status: ON, Wi-Fi has self-assigned IP address and will not able to connect to the internet

Selections from Wireless Diagnostics Report:

# --- Check Connectivity

# --- Bluetooth

  Power State : Off

  Paired Devices : 0

# --- Wireless Environment

  2.4 GHz Networks : 3

  5 GHz Networks : 0

  Current Channel Networks : 1

  Recommended 2.4GHz Channels : [ 11 2 3 5 7 8 9 10 ] [ 1 6 4 ]

  Recommended 5GHz Channels : [ 36 40 44 48 149 153 157 161 ]

# --- Network Configuration

  Primary IPv4 Interface : None

  IPv4 Address : None

  IPv4 Router : None

  Primary IPv6 Interface : None

  IPv6 Address : None

  IPv6 Router : None

# --- Debug Log Entries

10/09/14 19:17:15.2910 SMTP port is blocked

# --- Environment Test Cases

10/09/14 19:17:18.6760 Adopted country code <X0> doesn’t match <WIFIWJ> / <MX>

# --- Environment Summary

10/09/14 19:17:22.1590 Conflicting Country Codes

# --- Configuration Summary

10/09/14 19:17:22.1630 Custom DNS Settings

10/09/14 19:17:22.1630 LAN Connectivity Failure

So, the thing I get is “conflicting country code”? I don’t understand how this is suddenly an issue after 6 weeks.

Network Diagnostics:

I choose DHCP (because the wireless is a WEP and only requires a password).  There is a cable box (also wireless) connected to the internet, and no other routers/etc.  As a result I get “Unable to connect to the Internet, Network Diagnostics cannot fix the current networking problem."  Network Settings is yellow, ISP failed (red) Internet failed (red), Server failed (red).  This happens with any combination of selections (yes or no, DHCP or not) in the network diagnostics.

Solutions tried:

Manually inputting IP, routers, and DNS listed of other computers/phone.  I get the green light “connected to the internet” in the Network Preference Pane, but still the exclamation point on the Wi-Fi symbol on the menu bar.

Putting in alternative DNS settings.

Fixing permissions, no difference.

Restarting, no difference.

Resetting router, no difference.

Trashing internet preferences as listed in several other threads, no difference.

Resetting PRAM, no difference.

Reinstalling OS X Mavericks.  Backing up computer and wiping it to reinstall entire computer, no difference.

—--

So, I don’t know what I can do.  There are no solution online that I can find that “resolves the country code conflict.”  I am in a different country than the computer’s issue, but so are the other people who use the router (and so is the phone).

I hope I was thorough enough to describe my problem.  Thank you ahead of time for any help.