how can i permanently block dingdingding.com
Rather than try to block - it would be best to find why it is trying to connect.
Are you trying to connect to the site - I suspect not.
Clear browser cache - Were you intending to visit the site ?
If not start by clearing your browser cache and cookies, including 3rd party cookies and restart your browser.
If that resolves it you should be good to go.[br]If it doesn’t try running your browser with add-ons disabled.
If that resolves it, have you added or updated any add-ons ?
If so try disabling that add-on - and restart and try again.
If still not resolved and you are using Chrome based browser - try this suggestion by Avast Team member ‘lukor’ - What about page notifications? Here: chrome://settings/content/notifications ? Do you have all cleared?