GLPI Agent stops sending inventory and returns connection error - "500 Can't connect to GLPI server"

[emerson-gustavoo]

Bug reporting acknowledgment

Yes, I read it

Professional support

Still not applicable

Describe the bug

Notebooks running Windows 11 with the GLPI Agent installed work normally and send inventory correctly for some time. However, after a few hours or days, the agent stops communicating with the server and returns the following error:
500 Can't connect to GLPI server
(The requested name is valid, but no data of the requested type was found.)

This issue occurs randomly on about 10 out of 65 notebooks, and the affected devices vary over time. Restarting the notebook temporarily resolves the issue, but after some time, the error reappears.

Relevant Logs:

[Mon Feb 24 20:36:54 2025][error] [http client] internal response: 500 Can't connect to GLPI server (The requested name is valid, but no data of the requested type was found.), IO::Socket::IP configuration failed
[Mon Feb 24 20:36:54 2025][error] [http client] unexpected content, starting with: Can't connect to GLPI server (The requested name is valid, but no data of the requested type was found.)
[Mon Feb 24 20:36:54 2025][error] No supported answer from server at https://glpi-server/

To reproduce

Steps to Reproduce the Issue:
Install GLPI Agent on a Windows 11 notebook.
Configure the agent to synchronize with the GLPI server.
The agent works normally and sends the inventory.
After some time, the agent stops synchronizing and returns the 500 Can't connect error.
Restarting the notebook makes the agent work normally again.

Expected behavior

Expected Behavior:
The GLPI Agent should continue sending inventories without requiring a computer restart.

Operating system

Windows

GLPI Agent version

v1.12

GLPI version

10.0.17

GLPIInventory plugin or other plugin version

GLPI Inventory v1.4.0

Additional context

Installation Method:

@echo off
echo [INFO] Starting GLPI Agent installation...

REM Install GLPI Agent via Winget
winget install glpi-agent --custom="SERVER='https://glpi-server/' RUNNOW=1 NO_CATEGORY='virtualmachine' TIMEOUT='3600'"

REM Wait for installation to complete
timeout /t 10 /nobreak

REM Register GLPI Agent as a service to start at boot
"C:\Program Files\GLPI-Agent\glpi-agent.bat" --install
sc config glpi-agent start= auto
net start glpi-agent

REM Run GLPI Agent immediately to send the inventory
start "" "C:\Program Files\GLPI-Agent\glpi-agent.bat"
start "" "C:\Program Files\GLPI-Agent\glpi-agent.bat" --server=https://glpi-server/ RUNNOW=1 --no-category=virtualmachine

REM Check if the GLPI Agent service is running
sc query glpi-agent

echo [INFO] Installation completed! Press any key to exit...
pause

Tests Performed:
✅ Is the GLPI Server online? → Yes.
✅ Does the GLPI Agent work again after restarting the notebook? → Yes.
✅ Ping test to the GLPI server (ping glpi-server)? → Responds normally.
✅ Route test (tracert glpi-server)? → The route reaches the destination, but there is a timeout on one of the intermediate hops.
✅ HTTPS connection test (telnet glpi-server 443)? → Connection established successfully.
✅ DNS resolution test (nslookup glpi-server)? → The DNS correctly resolves the server's IP.
✅ Manual GLPI Agent test (glpi-agent --server=https://glpi-server/ --debug)? → Shows a connection error.

[g-bougard]

Hi @emerson-gustavoo

this looks as intermittent network problem. Even tracert seems to report intermittent problem. Maybe you just have an overloaded router in the middle, or the glpi server itself, who knows ?

In that case, anyway, this is a bad idea to change TIMEOUT to 3600. Keep the default value of 3 minutes. Your timeout value means agent may wait an hour for a server answer. And if its request has been drop, meaning the server won't even try to answer, this can mean agent will wait one hour for nothing.

On network connectivity issues, glpi-agent should try again the request soon, but not very soon if timeout is set to one hour.

As I don't see any glpi-agent issue, I'll transfer your issue as a discussion.

[g-bougard]

Well, GH seems to have trouble to convert it as a discussion. Will retry later.

[emerson-gustavoo]

We can rule out network issues since we have employees both in the office and working remotely, and the problem occurs in both scenarios. Additionally, the GLPI server is hosted in a datacenter virtualized on Proxmox, and all infrastructure VMs run the GLPI Agent without any issues.

The strange behavior happens only on employees' laptops: after being powered on for an extended period, the GLPI Agent loses connection to the server and stops sending inventories. However, as soon as the laptop is restarted, everything returns to normal automatically.

It seems that the GLPI Agent service is unable to restore the connection on its own after running for a prolonged period.

[g-bougard]

after being powered on for an extended period

after running for a prolonged period

Can you be more accurate ?

You said in issue description:

However, after a few hours or days, the agent stops communicating with the serve

Anyway, still try to not set TIMEOUT at one hour on that computers. This will even change the time glpi-agent will wait before retrying. You can eventually make it lower than the default of 180 seconds (3 minutes).
You should also enable debug=2 on it. Try at least on one test computer, setting this in registry and restarting the service just after.

[emerson-gustavoo]

To solve this issue, I created a script that adds a task to the Task Scheduler to check whether the GLPI Agent is running. If it isn't, the script automatically restarts it. This was necessary because when a laptop remained on for more than two days, the agent would lose connection and require manual intervention to restore functionality.

[g-bougard]

Hi @emerson-gustavoo

I asked you questions in response to your previous comment. If there's a problem glpi-agent side, I need answers. Or do you have some unknown network issues you still didn't figure out and this is the only way you found to fix it ?

[emerson-gustavoo]

I apologize for the delayed response. I conducted some tests on a notebook, reducing the timeout to 180. However, even after running continuously for two days, the GLPI Agent stopped communicating. The log remains the same as mentioned in the first post.

I didn't enable debug mode, as I forgot to do so.

However, I am certain that this is not a server-related issue. The server where the GLPI Agent is hosted is monitored by Monit and does not show any failures.