link availability trigger does not fire on dashboard

[Shadowroot]

Good Morning! I have a problem with triggering a firewall that we monitor, when the link is unavailable, the alert is not displayed on the problems dashboard. other links that monitor us trigger normally, we use the same settings as those other links with triggering in operation but the problem persists. Has anyone already encountered this problem? I thank you in advance.

[ik_zelf]

Does the item on which that trigger is defined receive data?
Is that item valid?
How do you get the data of that item? (and how frequent?)