Alert system is throwing alerts for machines that are up and running (and saying they're down)

Hello! Very new to LibreNMS. It was actually already set up before I came on board and I’ve never used it before (and there’s no internal documentation…)

I’m running into an issue where some of my machines (4 of them) are throwing alerts saying they’re “down” when they aren’t. I’ve acknowledged the alerts for now, so that I’m not being overwhelmed with emails anymore, but I still need to get that fixed. I’ve looked through some of the logs and I’ve ran the “manual discover” with both ./discovery-wrapper.py along with manually hitting the “discover device” blue box under the actual machine itself, and I’ve fixed up (most) of the issues in my validate.

./validate.php

====================================

Component Version
LibreNMS 1.41-53-g9c250df
DB Schema 255
PHP 7.0.30
MySQL 5.5.56-MariaDB
RRDTool 1.4.8
SNMP NET-SNMP 5.7.2

====================================

[OK] Composer Version: 1.6.5
[OK] Dependencies up-to-date.
[OK] Database connection successful
[FAIL] Database: missing column (users/updated_at)
[FAIL] Database: missing column (users/remember_token)
[FAIL] We have detected that your database schema may be wrong, please report the following to us on IRC or the community site (https://t.libren.ms/5gscd):
[FIX] Run the following SQL statements to fix.
SQL Statements:
ALTER TABLE users ADD updated_at timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP AFTER created_at;
ALTER TABLE users ADD remember_token varchar(100) NULL AFTER updated_at;

So there’s that also. Not entirely sure where to go from here… Anyone have any thoughts? I’ll be happy to past what I need.

Next to the device it will say why it’s down, icmp or snmp. Find out that first.