It is not consistent that is what makes it difficult to figure out what the issue is. It may have been the relatively recent push on homekit that broke the streams or could be something else. It works sometimes but not everytime and usually not for very long stretches.
I guess it is reassuring to know that others have the same issues. I would like to know if there are any configuration differences between my setup and those that do not have any issues.
I didn’t do more, but then again, I only have the weather station part, not cameras and stuff like that.
Just to be clear, rebooting the camera completely fixed my problem.
I really had 2 problems :
local_url, so the integration set it to null and switched to cloud mode.vpn_url (used in cloud mode) wasn’t updated in HA. According to the Netatmo documentation, it’s supposed to expire after 3 hours. So after 3 hours, I wasn’t able to see the live stream.Now after a few days, it seems like both my local_url and vpn_url are right.
I’m not sure it’s the same issue as @GlennHA and @Samsonice though. I changed my Wifi (and all my network configuration really, I got fiber 
) a few days before noticing the issue and I guess that the camera doesn’t report its new local IP address to Netatmo when you change it.
The chapter Video access in this page really helped me understand my problem. If you’re logged in you can try the API directly on this page and compare the results with your entity attributes.
edit:
When I say “cloud mode”, I mean that the integration use <local_url>/live/index.m3u8 when local_url is set to get the live stream and <vpn_url>/live/index.m3u8 when it’s not. That’s what I call cloud mode.
Thanks for your detailed insights.
Just a follow-up.
Today, I upgraded HA to 2021.10.5 from 2021.9.x, and now HA receives snapshots from my presence camera again.
So I guess it must have been some bug introduced in the 2021.8.x version. A bug that now seems fixed.
Thanks for the feedback. Actually I think this was related to a firmware update on the Netatmo side, but regardless, it is fixed now and good to know it is working now.
I very rarely get any snapshots from anything other than the doorbell; however, I do like the ability to now see the recorded events directly in HA. The Media Sources seem to only work for my four Presence cameras and not the doorbell. I don’t know if that is due to being different systems or due to the fact that my doorbell is setup via homekit controller.
I’m not sure when media sources was added since I don’t use the default config. I periodically look at what is included and see if I am missing something I may want. I don’t know if others knew about this or I just completely missed any mention of this by anyone else. I did not notice the ability to view recorded events until 2021.10.
The issue is twofold. The Netatmo integration currently does not support the doorbell camera since Netatmo did not yet release an official API for it. Therefore there are no entries for that device in the media browser. I have no idea about whether the homekit integration supports this feature in general and specifically for the Netatmo doorbell camera.