Set up Jira webhook manually in case something went wrong.
To set up Jira webhook, follow the steps:
Open your Jira in the browser;
Click on the Settings icon in the upper right corner;
Scroll Jira Settings to the bottom and select Webhooks;
Click Create a WebHook in the upper right-hand corner;
Enter a webhook name;
Switch to Leverice and copy the Webhook URL at the bottom of the Jira Settings window;
Switch back to Jira and paste the webhook URL into the URL field;
Scroll down to the Events section;
Enter the following text into the All issues field: project = [project key]
Copy project key from the Project key field in Leverice.
Tick all Issue and Comment checkboxes right under the All issues field;
Scroll down to the bottom of the page and click Create.
The display of the following page confirms that the webhook is successfully created!