Hi  @Sadiqus 

First, please let us know the following to understand your VPN config:

1. did you create IPsec tunnel for all the 4 sites, and all of them can communicate with each other? 

2. Is the Internet of the 4 sites still working?

3. Go to Insighs > VPN Status, are the VPN tunnels still showing on this page?

4. Did there any change on the outbound IP addresses of the four sites?

  @Vincent-TP 

1. So, on the OC200 controller (2 locations) I have a connection (tunnel) with the second location and a second connection with location 3 (which is on another controller, it is a software controller that has 2 managed locations), on the second controller (software) I have a connection with location 4 which is on the same controller. 

2. Yes, the internet works perfectly in all 4 locations.

3. On Insights>VPN Status doesn't show any connection just like in your screenshot. 

4. There were no changes to IPs, I have 4 fixed IPs from my ISP.  

I hope this outline will make you understand better. 

  @Sadiqus 

Thank you so much for taking the time to post the issue on TP-Link community!
To better assist you, I've created a support ticket via your registered email address, and escalated it to our support engineer to look into the issue. The ticket ID is TKID250216447, please check your email box and ensure the support email is well received. Thanks!
Once the issue is addressed or resolved, welcome to update this topic thread with your solution to help others who may encounter the same issue as you did.
Many thanks for your great cooperation and patience!

@Vincent-TP @MR.S 
Over the weekend it only came back from one direction, the connection appears at Insights>VPN Status, but sometimes it only works from one direction, sometimes not at all. also started to appear in the logs: Gateway IPsec Module Information    
WAN2: Lifetime of the SA created in phase 1 of IKE negotiation expired. (Peers=94.53.244.211<->94.53.106.244)
Feb 10, 2025 10:31:21    

Gateway IPsec Module Information    
WAN2: Lifetime of the SA created in phase 2 of IKE negotiation expired. (Peers=94.53.244.211<->94.53.106.244, SPI=3244311518)
Feb 10, 2025 10:31:14 
or like:  
Gateway IPsec Module Information    
WAN2: Phase 1 of IKE negotiation failed. (Peers=94.53.244.211<->94.53.231.180, Error=14)
Feb 09, 2025 09:48:06    

Gateway IPsec Module Information    
WAN2: Phase 1 of IKE negotiation failed. (Peers=94.53.244.211<->94.53.231.180, Error=14)
Feb 09, 2025 09:48:04
Gateway IPsec Module Information    
WAN2: IPsec connection was disconnected passively. (Peers=94.53.244.211<->94.53.231.180)
Feb 09, 2025 09:59:50
Gateway IPsec Module Information    
WAN2: Enable DPD successfully. (DPD-Interval=30, Peers=94.53.244.211<->94.53.231.180)
Feb 09, 2025 09:49:41

  @MR.S 

it's not connecting, both are initiator
 

  @MR.S 

I have seen the error but i corect it! still nothing no connection!