I am questioning here because I believe that here I will find a more precise and technical answer than the forum (link).

Our Zabbix came from a migration from version 1.8.11, so several items continued with certain parameters out of date. A camera host was showing a lot of alerts, so replace the last () <> 1 function with max (5m) = 0, but I also changed the item key, as I said in the title of this post, and after that, not only the alerts decreased, as the collection stabilized, registering only 1 now (up). When it was ["http" ,, "80"] I was recording about fifty '0' (down) a day, which I came to think that the camera or the link could be in trouble with.

Before:

Name: Is CFTV CCE_ENT_FOYER_02 port 80 alive
Type: Simple check
key: net.tcp.service["http",,"80"]
Type of information: Numeric (unsigned)
Update interval: 5m
History: 3650d

After:

Parent items: Template App HTTP Service
Name: HTTP service is running
Type: Simple check
key: net.tcp.service[http]
Update interval: 1m
History: 1w

The Zabbix Server log does not show me any related information.

If I understand why the stability problem of the old item was corrected, I will have a more concrete argument to present to my boss and then move from the other hosts (we would have about 400 more cameras to change, few have this instability).