Unable to connect to Wi-Fi network "The Wi-Fi network " " could not be joined."

[gdthreepwood]

Evening all,

My first time on these forums, so hoping someone could offer some assistance with this issue.

I have a 2015 iMac with 5K Retina Display that is experiencing a curious fault. It is currently unable to connect to my home Wi-Fi network and displays the following message whenever I try and connect:

"The Wi-Fi network " " could not be joined.
Try moving closer to the wireless router. Alternatively run Wireless Diagnostics to troubleshoot."

The iMac is in a location with a strong Wi-Fi signal and all other devices within the same location can connect to this SSID (including the MacBook Pro on the same desk as the iMac on which I am typing this). I have used Wi-Fi explorer to troubleshoot, and can see no issues with the strength of the network, interference from other channels etc.

I have tried deleting the SSID from KeyChain, and then re-connecting from scratch to no avail. I took the iMac into the Genius Bar but when tested, it connected immediately to the in-store Wi-Fi without any issue. I also have a separate Windows 10 Bootcamp partition which can connect to the same network without any issue, which would seem to rule out hardware. The only thing that they could suggest following my own triage, was to re-install OSX which I did, and which did appear to fix the issue. Upon a subsequent boot-up of the system however, the fault has re-occurred again.

I am an experienced IT Support Engineer with a strong Windows background (still making the full adjustment to Mac), and am at a complete loss to explain this behaviour. Clearly, this is not hardware else the Windows partition would also have issues and I could not connect to other networks. Likewise, this is clearly not 100% software, as the iMac can connect to all other networks tested. Finally, this is clearly not 100% a router issue, as every other device in the house can connect without issue including other MacBook's, iPhone's etc.

I suspect that some corruption has taken place deep within a config file that is then being cached for this SSID specifically, however I have not been able to evidence this, and likewise would have expected the re-install of OSX to resolve this type of fault.

Can anyone offer any other suggestions for where to go with troubleshooting this issue?

Regards,

gdthreepwood

 

[MacInWin]

Welcome to the forum!

Is the name of the WiFI network actually " "? I.e, a blank space? That may be part of the problem. Most WiFI spots have more than just a blank space for a name. Now a blank space IS a valid character, but I'm wondering if there is something about such a strange name that might be causing the problem. How does the name appear in System Preferences/Network?

 

[gdthreepwood]

Thanks for the warm welcome MacInWin!

No, the SSID is not " ", I've just replaced by actual SSID with the blank space. The actual SSID is similar to ABC103D.

Regards,

gdthreepwood

 

[MacInWin]

Ah, ok, it was a thought...

In System Preferences/Network click on the WiFi network on the left column, then on Advanced in the right pane. Find the network name and highlight it, then click on the "-" symbol below the window to forget the network completely. Then try reconnecting. It sounds like something is amiss in the stored material for that wifi network and that sequence will allow you to reset it and re-establish the connection.

 

[RadDave]

Thanks for the warm welcome MacInWin!

No, the SSID is not " ", I've just replaced by actual SSID with the blank space. The actual SSID is similar to ABC103D.

Hello and welcome to the forum! Well, you've seem to have done about everything! I'm not sure what ISP or broadband technology you are using nor whether you have a modem + router (or a combo device), but have you tried to 'power cycle' the modem and router? Sometimes has help me get a device to connect even when the others are doing fine; also assume that your router firmware is up to date; finally, does your OS X partition connect if your computer is cabled to your router? Good luck - Dave

 

[gdthreepwood]

Ah, ok, it was a thought...

In System Preferences/Network click on the WiFi network on the left column, then on Advanced in the right pane. Find the network name and highlight it, then click on the "-" symbol below the window to forget the network completely. Then try reconnecting. It sounds like something is amiss in the stored material for that wifi network and that sequence will allow you to reset it and re-establish the connection.

Tried that, but unfortunately no luck when attempting to reconnect after. Any further ideas?

 

[gdthreepwood]

Hello and welcome to the forum! Well, you've seem to have done about everything! I'm not sure what ISP or broadband technology you are using nor whether you have a modem + router (or a combo device), but have you tried to 'power cycle' the modem and router? Sometimes has help me get a device to connect even when the others are doing fine; also assume that your router firmware is up to date; finally, does your OS X partition connect if your computer is cabled to your router? Good luck - Dave

Hi Dave - thanks for the welcome. Cabled works fine. Unfortunately my LAN connection is currently not working in the room containing the iMac which is why I've had to resort to wireless for the time being, which in turn has shown the fault.

I have power cycled the router, unfortunately to no avail. This does seem to be inherent to the OSX partition only. Do you have any further ideas?

 

[MacInWin]

What happened when you tried to reconnect? What does "no luck" mean? It helps if you can be a bit more detailed as we cannot see your system or the responses.

 

[gdthreepwood]

What happened when you tried to reconnect? What does "no luck" mean? It helps if you can be a bit more detailed as we cannot see your system or the responses.

Apologies, I meant that the same message appears again i.e., unable to connect to Wi-Fi network.

 

[MacInWin]

So, the connection shows the WiFi router, but when you put in the password, it rejects it? Sounds like you have the password wrong, or the protocol for the password wrong. Passwords are case-sensitive, so check that, and then your wifi router for the protocol and make sure you see the same thing in the System Preferences/Network/Wifi/Advanced window as well. I can testify from my own experience that I spent hours troubleshooting a WiFi issue only to find out I was using the wrong password. D'oh!

 

[RadDave]

Hi Dave - thanks for the welcome. Cabled works fine. Unfortunately my LAN connection is currently not working in the room containing the iMac which is why I've had to resort to wireless for the time being, which in turn has shown the fault.

I have power cycled the router, unfortunately to no avail. This does seem to be inherent to the OSX partition only. Do you have any further ideas?

Hi again - well, with what you've already done, including a visit to an Apple store, and w/ Jake's suggestions, I just had the 'power recycle' and my few other comments - sorry. Hope that you solve the issue soon - good luck. Dave

 

[ferrarr]

Have you compared the wifi settings on the MBP to the iMac? Something in there has to be different.

Go into System Preferences > Network and then with wifi selected click on Advanced.

Have you tried moving the iMac closer, just to see if it will help?

 

[gdthreepwood]

Have you compared the wifi settings on the MBP to the iMac? Something in there has to be different.

Go into System Preferences > Network and then with wifi selected click on Advanced.

Have you tried moving the iMac closer, just to see if it will help?

I've had the iMac sat next to the router, and still receive the same message!

I've performed a comparison between the iMac and the MBP and everything is identical.

I've also tried to create a new user in case the fault was with one of the library files, but the new user also has the same issue.

Does anyone have any further suggestions?

Regards,

gdthreepwood

 

[ferrarr]

Have you tried changing the SSID in the router?

 

[gdthreepwood]

Have you tried changing the SSID in the router?

Yes, I have. Still encounter the same problem when attempting to connect to the new SSID.

One other website which describes a similar issue suggested removing all files (not just the airport plists) from ~/Library/Preferences/SystemConfiguration.

Would this be safe to try?

 

[gdthreepwood]

OK - this is interesting. I've managed to force a connection using the following terminal command:

networksetup -setairportnetwork en1
"WIFI_SSID_I_WANT_TO_JOIN" WIFI_PASSWORD

However, although the network is connected, I am seeing significant packet loss when running a continual ping, and there is a huge amount of latency on the responses that are received. Attempting to access even simple websites results in a timeout. I have managed to get to this position once before, however upon a reboot of the system, the connection was lost and I was right back to square one.


Does this provide any further evidence to suggest what is at fault here?

 

[MacInWin]

Yes, that says the signal from the WIFI is weak into the electronics of the MBP. That weakness could be the WiFi router (but probably isn't if other pc's can see the signal OK), or weak receiver (not really likely, given the store experiment) or interference on the WiFi channel the MBP is using with the router (most likely). Is the WiFi router dual band? If it is, then try forcing the iMac to the OTHER frequency band. You can do that by giving the two bands two different SSIDs on the router, then selecting one and the other in the iMac. Of course, doing this will also mean every other device will need to "learn" these two new networks, but it could work. In my neighborhood I noticed that most of my neighbors were all on the 2.4 band, so I renamed the SSIDs on my router to "My Router 2.4" and "My Router 5" and then on all my devices picked "My Router 5" to force them to use the 5Ghz band. It could be the iMac is seeing interference, being the last to the party, so changing bands may help.

 

[gdthreepwood]

Yes, that says the signal from the WIFI is weak into the electronics of the MBP. That weakness could be the WiFi router (but probably isn't if other pc's can see the signal OK), or weak receiver (not really likely, given the store experiment) or interference on the WiFi channel the MBP is using with the router (most likely). Is the WiFi router dual band? If it is, then try forcing the iMac to the OTHER frequency band. You can do that by giving the two bands two different SSIDs on the router, then selecting one and the other in the iMac. Of course, doing this will also mean every other device will need to "learn" these two new networks, but it could work. In my neighborhood I noticed that most of my neighbors were all on the 2.4 band, so I renamed the SSIDs on my router to "My Router 2.4" and "My Router 5" and then on all my devices picked "My Router 5" to force them to use the 5Ghz band. It could be the iMac is seeing interference, being the last to the party, so changing bands may help.

Unfortunately, the router is only single-band (2.4Ghz only), so I don't have the option to try and alternative frequency. I have changed the channel of the router, but this does not seem to have had an effect.

Following additional troubleshooting steps suggested here: http://www.igeeksblog.com/how-to-fix-wi-fi-issues-in-mac-os-x-el-capitan/ I have managed to connect to the Wi-Fi by creating a new location, DNS entries and manually altering the MTU. Although this has got me connected, I am still suffering with terrible latency and packet loss and attempting to load any website results in a download speed akin to a 28.8Kb/s modem .

Does this help somewhat?

 

[MacInWin]

At this point a new WiFi router may be the best solution. Get a dual-band one, then move to the 5GHz band.

 

[mrplow]

Can I suggest something?

Temporarily remove the password from your wifi.
Can you connect now?

What sort of encryption is being used on your wifi? And what channel is in use?

Apologies if this has been tried. Couldn't see it in the thread