The documentation for re-triggering a CRC check on the webhook shows a URL of the form:
https://api.twitter.com/1.1/account_activity/all/:env_name/webhooks.json
When called, this returns a 404 status code and a “Sorry, that page does not exist”.
The correct URL for the PUT is:
https://api.twitter.com/1.1/account_activity/all/:env_name/webhooks/:webhook_id.json
-ch