IPSec connection created by ACC can not be deleted nor updated

Hi Folks,

I created an IPSec Connection on my ACC for two of my ASG's. According to the ACC the deployment to one of the both did not complete though the objects were created on the ASG. Now I am not able to edit/delete the tunnel spec neither in ACC nor in the ASG. ACC says "Error: VPN is currently being modified or during removal Id: 10403" and ASG says "managed by ACC".
Does anyone of you know how to solve this?

Thanks in advance.

(ASG 425 HA [Sophos] V8.306 & ASG 320 HA V8.305)