Quite recently, we updated Connect documentation about installation secret being out of sync. For quick reference here are the 3 main paths (see docs for more details on trade-offs):
- Bump up the micro version of your app so that the daily lifecycle event can send a newly issued secret
- Request an administrator of the site to uninstall and reinstall the app, which will send a new secret immediately
- Submit a Developer Support ticket requesting a single site to be reset