VPN no longer working after 11.7.2 update. It´s working fine on 11.7

Same for me. L2TP seems to be broken for now with macOS BigSur 11.7.2.

I have found this workaround (not a fix):

If your VPN provider supports "Cisco IPSec" (beside L2TP), you can add another VPN connection using this connection type. For me, that was a lifesaver.

Thanks Apple developer's team, for fixing it. Now, L2TP works after updating to Big Sur 11.7.3, and I recommend you update to 11.7.3

Tue Jan 24 13:58:01 2023 : IPSec connection started
Tue Jan 24 13:58:01 2023 : IPSec phase 1 client started
Tue Jan 24 13:58:01 2023 : IPSec phase 1 server replied
Tue Jan 24 13:58:02 2023 : IPSec phase 2 started
Tue Jan 24 13:58:02 2023 : IPSec phase 2 established
Tue Jan 24 13:58:02 2023 : IPSec connection established
Tue Jan 24 13:58:02 2023 : L2TP sent SCCRQ
Tue Jan 24 13:58:03 2023 : L2TP received SCCRP
Tue Jan 24 13:58:03 2023 : L2TP sent SCCCN
Tue Jan 24 13:58:03 2023 : L2TP sent ICRQ
Tue Jan 24 13:58:03 2023 : L2TP received ICRP
Tue Jan 24 13:58:03 2023 : L2TP sent ICCN
Tue Jan 24 13:58:03 2023 : L2TP connection established.
Tue Jan 24 13:58:03 2023 : L2TP set port-mapping for en1, interface: 5, protocol: 0, privatePort: 0
Tue Jan 24 13:58:03 2023 : using link 0
Tue Jan 24 13:58:03 2023 : Using interface ppp0
Tue Jan 24 13:58:03 2023 : Connect: ppp0 <--> socket[34:18]
Tue Jan 24 13:58:03 2023 : sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x1380e658> <pcomp> <accomp>]

Jose-Drago wrote:

VPN no longer working after 11.7.2 update. It´s working fine on another Mac running 11.7

What could be the fix?

You don't say what VPN. Contact the maker of VPN to check if there is a needed update.

With today's 11.7.3 update, VPN has started working again...

For the sake of completeness: With macOS 11.7.3 the bug seems to be fixed

11.7.3 cures the issue with VPN. Apple did listen!!

"Thank you" to Apple for caring... It is quite obvious that l2tp is broken on purpose, because no such problem was found in other OS versions (Monterey and Ventura). And to switch to Monterey, my MacBook PRO is getting too hot, I doubt that the situation will be better on an officially unsupported Ventura.

I had to switch to Ikev2 and VPN in test mode. As a result, we stayed on Ikev2, because it does not require a third-party client.

What to do to users who do not have admin access to network equipment or other restrictions on the part of information protection, I will not know. 

Once again, "Thank you" to Apple for caring...

I have seen several complains in different communities regarding VPN and Monterrey too, so it seems that it does not work with some updates. I have moved to OpenVPN and it works so ... I think that I will not be back to L2TP just in case.

Same problem at my side, after upgrade Big Sur to 11.7.2 problem with L2TP/IPSEC VPN connection.

There are following messages in /var/log/ppp.log :

Mon Dec 19 12:54:25 2022 : publish_entry SCDSet() failed: Success!

Mon Dec 19 12:54:25 2022 : publish_entry SCDSet() failed: Success!

Mon Dec 19 12:54:25 2022 : l2tp_get_router_address

Mon Dec 19 12:54:25 2022 : l2tp_get_router_address x.x.x.x from dict 1

Mon Dec 19 12:54:25 2022 : L2TP connecting to server 'y.y.y.y' (y.y.y.y)...

Mon Dec 19 12:54:25 2022 : L2TP can't set L2TP server address: Cannot allocate memory

Mon Dec 19 12:54:25 2022 : IPSec connection started

Mon Dec 19 12:54:25 2022 : L2TP error sending Hello (Destination address required)

Mon Dec 19 12:54:25 2022 : Failed to send L2TP hello trigger. tried 0, max 10

Mon Dec 19 12:54:26 2022 : L2TP error sending Hello (Destination address required)

Mon Dec 19 12:54:26 2022 : Failed to send L2TP hello trigger. tried 0, max 10

Mon Dec 19 12:54:27 2022 : L2TP error sending Hello (Destination address required)

Mon Dec 19 12:54:27 2022 : Failed to send L2TP hello trigger. tried 0, max 10

Mon Dec 19 12:54:28 2022 : L2TP error sending Hello (Destination address required)

Mon Dec 19 12:54:28 2022 : Failed to send L2TP hello trigger. tried 0, max 10

Mon Dec 19 12:54:29 2022 : L2TP error sending Hello (Destination address required)

Mon Dec 19 12:54:29 2022 : Failed to send L2TP hello trigger. tried 0, max 10

Mon Dec 19 12:54:30 2022 : IPSec connection failed

If you join the Developer Program and then the public Beta Program, you can download and install 11.7.3

Exactly the same problem here.

It worked fine until macOS 11.7.1, but now none of the "L2TP over IPSec" VPN connections work anymore.

In the ppp.log log file the following messages appears:

L2TP can't set L2TP server address: Cannot allocate memory

Sat Dec 17 10:48:03 2022 : IPSec connection started

Sat Dec 17 10:48:03 2022 : L2TP error sending Hello (Destination address required)

Sat Dec 17 10:48:03 2022 : Failed to send L2TP hello trigger. tried 0, max 10

Have the same issue on my iMac after updating to Big Sur 11.7.2. Any solution for this issue?

ppp.log:

L2TP can't set L2TP server address: Cannot allocate memory

I solved the problem by installing FortiClient VPN. I'm lucky my company bought the license. Free download is still possible.

I have the same issue. None of my "L2TP over IPSec" VPN connections work any more. They are set up with a user password and shared secret. Tried restarting; Tried recreating the connection and it still doesn't work.