I think you need to be following the documentation here:
https://zmeventnotification.readthedocs.io/en/latest/guides/hooks.html#troubleshooting
Specifically
One of the big reasons why object detection fails is because the hook is not able to download the image to check. This may be because your ZM version is old or other errors. Some common issues:
Make sure your objectconfig.ini section for [general] are correct (portal, user,admin)
For object detection to work, the hooks expect to download images of events using https://yourportal/zm/?view=image&eid=<eid>&fid=snapshot and possibly https://yourportal/zm/?view=image&eid=<eid>&fid=alarm
Open up a browser, log into ZM. Open a new tab and type in https://yourportal/zm/?view=image&eid=<eid>&fid=snapshot in your browser. Replace eid with an actual event id. Do you see an image? If not, you’ll have to fix/update ZM. Please don’t ask me how. Please post in the ZM forums
Open up a browser, log into ZM. Open a new tab and type in https://yourportal/zm/?view=image&eid=<eid>&fid=alarm in your browser. Replace eid with an actual event id. Do you see an image? If not, you’ll have to fix/update ZM. Please don’t ask me how. Please post in the ZM forums