Lock failed to complete the network security exchange


I’m trying to get my August Pro lock connected to Smartthings and am getting the following error when I try to pair: “The lock failed to complete the network security exchange…”

I’ve tried excluded, and re-pairing, moving the lock right beside the hub, resetting the lock, restarting the hub but end up with the same error every time.

Does anyone have any ideas? I’ve found some similar threads but haven’t been able to find a solution


(Simon) #2

If you go into the IDE and click on the device, what do you see in the field marked Raw Description?

If the device included in secure mode it the string should start with “zw:Ls”.

It would be with excluding, do a Z-wave repair and then include again. This time with it sitting on top of the hub. Also, does the device have a different pairing sequence for secure and not? I know some devices need a different kind of button push to get them to include in secure mode.


Hi Simon, thanks for the help, here’s the raw description:

zw:L type:4003 cc:5E,55,98,9F

I’ve tried excluding, repairing and including even with it on top of the hub. The August Pro had paired successfully before, although over the last couple weeks it had gotten a little flaky so I had excluded it, factory reset it and included it again. I don’t believe there’s any tricks on the August Pro side for getting it to pair in secure mode, in fact when it pops up, it says Smartthings only supports S0 security, rather than S2 like the lock does.

(www.rboyapps.com - Make your home your butler!) #4

No you can’t control nor can any DTH control the pairing process. That’s between the hub and the lock. It should automatically fall back to S0 if S2 fails and continue working. However if I remember the specs correctly it will not function if it fails to negotiate S0. If it doesn’t pair it means the exchange failed and you need to try again.
Often distance is a crucial factor, sometimes pairing within 3ft of the hub helps.

If this problem started recently it could be related to a hub firmware update (since pairing is exclusively controlled by the hub). You may want to report it to ST support and have him investigate the hub logs to see why it’s no longer pairing with S0

(Jimmy) #5

A S2/S0 warning is normal with the August Pro since SmartThings doesn’t support S2, but this error may be different. Could you control it from the SmartThings app at all?


Yeah, I’m guessing it’s hub firmware related as I was able to pair it previously. Where as now it won’t pair whether it’s 20ft away, on top of the hub or anywhere in between.

Jimmy, I’m not able to control it at all, it shows up and in the locked state, but it can’t be unlocked through z wave and when I manually unlock it, smartthings still shows it as locked.

(Jimmy) #7

Bummer. It could also be lock firmware related. I know mine has received a couple since i’ve had it. One of them killed z-wave communications, but a reset via the August app and a replace in SmartThings fixed that.


So I tried picking up a new August Pro lock today just to test, and am running in to the exact same error, so assuming I can rule out the lock hardware it looks like it’s something that is Smartthings hub related.

If anyone else has any ideas, I’m all ears

(Jimmy) #9

Can you post a screen shot of the error?


Sure thing:

(Jimmy) #11

ohhh, its on the SmartThings side. Interesting. Don’t think i’ve ever seen that. Are you using any custom device handlers for locks?


Yeah currently I’m using the Rboy handler, I suppose I can try removing the device handler and trying again, but I was receiving the same error without it, and tried using it in an attempt to resolve the issue:

(Jimmy) #13

hmmm, removing any community handler was going to be my suggestion. And it sounds like you’ve tried pairing it within 3 ft or so of teh hub. Not really sure what to suggest other than exclude, try again and repeat until it works :confused:

(www.rboyapps.com - Make your home your butler!) #14

Try this, power off the hub for about a minute and then power it back on. Exclude first and then try to pair within 3ft of the hub. This error is a basic z-wave pairing issue (even before the DTH comes into the picture, it isn’t able to negotiate on the communication protocol) and may be an issue with the hub firmware. We had seen this issue with another vendors product when working with some plugs, sometimes power cycling the hub gives it a fresh start.

If it still does not work, ping me and I can request the ST engineer who had worked with us back then to resolve the issue to try and take a look at what’s going on.


Thanks RBoy, I’ll give that a shot this evening and let you know how it goes.