How long webhook stays active?

Hi guys,

I'm using ADOBE SIGN API.
I'm using one webhook for all notifications. Idea is when signing notification is fired from webhook I need to retrieve signed document. I have implemented this and it works ok.

Issue:
After sometime (2 or 3 days) webhook is deleted (not set to inactive, it is removed) and I don't get notifications anymore.

Can someone from API crew give me some advice on this? What might be causing this? Can I set webhook to be active indefinitely? Should it expire, am I the only one with this issue?

What is the best case scenario to implement?

Thanks!