Every validator on the Avalanche network keeps track of the uptime of other validators. You can see the connections a node has by calling
info.peers, as well as the uptime of each connection. This is only one node’s point of view. Other nodes may perceive the uptime of your node differently. Just because one node perceives your uptime as being low does not mean that you will not receive a staking reward.
The likely reason that your node is not connected to another node is that NAT traversal failed and you did not start your node with
--public-ip=[NODE'S PUBLIC IP].