you can reproduce my environment by the following code:
```
docker run --name=jenkins --restart=always -p 127.0.0.1:8080:8080 -p 50000:50000 -v jenkins-data:/var/jenkins_home jenkins:alpine
```

When I was using the gogs-plugin, and set-up the same secret in both gogs and Jenkins' gogs-plugin, the webhook actually work really well.
Here comes the problem, after I restart the whole server, the secret showed in the job is still the one I inputed before, however, the webhook actually isn't working!
I have checked post json content from gogs, they are the same as before.
It's the fault on the jenkins side--you actually need to save your secret again in the job configuration page and everything would work as you expected.

Anyway, thank you for your great job!

—
update:
Or I guess, the secret isn't loaded successfully from your back-end database as expected.