"Someone Is Currently Logged Into the APC Management Web Server": How to Get Back In

You type the IP address of an APC UPS or PDU into your browser and, instead of the login page, you get a notice that “someone is currently logged into the APC Management Web Server.” The Network Management Card (NMC) inside the device only accepts a limited number of sessions, and one is already taken, often by someone who closed the browser without logging off. The quickest fix is to wait a few minutes for that session to time out; if that’s not an option, end the session from the command line or restart only the card’s management interface.

The steps below follow APC’s user guides for the Network Management Card 2 (AP9630, AP9631, AP9635) and the older AP9631 firmware. Menu paths can differ on other cards and firmware versions, so check the guide for your model.

What causes the “someone is currently logged in” message

APC’s AP9631 guide lists “Someone is currently logged in…” as a browser error whose cause is simply that someone else is logged on. On that firmware, only one user at a time can log on to the card.

The catch is how sessions end. The guide explains that the inactivity timer keeps running if a user closes the browser window without clicking Log Off. Until the timer expires, the card still treats that user as logged on, and nobody else can get in. With the default setting, that’s 3 minutes.

On NMC 2 firmware, an administrator can allow several users at once. Without Allow Concurrent Logins, you’re still limited to one session.

Quick fix summary

Fix	When it helps	Risk
Wait for the session timeout	Someone closed the browser without logging off	None
Log off the open session	You know which PC or tab still has it open	None
Log in with SSH, Telnet or serial and restart the interface	You can’t wait and can reach the CLI	Low, if you use only the management interface reboot
Press the card’s Reset button once	You’re at the device and nothing else works	Low; pressing twice starts password recovery

How to fix it

Fix 1: Wait for the session to time out

1. Close every browser tab that points at the card’s address.
2. Wait at least 3 minutes, which is the default timeout. If your admin raised it, wait that long instead (NMC 2 allows 1 to 60 minutes).
3. Open the card’s address again.

Tip: If you know someone left the page open on another PC, ask them to click Log Off at the top right of the APC page. That frees the session right away.

Fix 2: Use the command line over SSH or Telnet

If console access is enabled on the card, you can reach its command line interface (CLI) from another computer. SSH encrypts your user name and password; Telnet doesn’t, so use SSH when the card offers it.

1. Open Command Prompt or PowerShell. Windows 10 version 1809 and later include the OpenSSH client.
2. Connect (replace the address and user name with yours):

ssh apc@192.168.1.50

For Telnet, the Windows telnet client must be installed first, and the default port is 23:

telnet 192.168.1.50

3. Log in with an Administrator account.
4. Restart the management interface:

reboot

In the CLI reference of APC’s AP9631 guide, reboot restarts the interface of the Management Card, which ends the stuck web session. Check the CLI guide for your firmware if the command differs.

Important: Restarting the management interface doesn’t turn off the UPS output, but the CLI and web menus also contain commands that do. Don’t run UPS power actions such as Reboot UPS or ups -c, and don’t run resetToDef or Reset All, which reset the card’s configuration to defaults.

The older AP9631 guide ranks access priority as serial console first, then Telnet or SSH, then web. If the CLI also refuses you, use the serial console (Fix 3) or wait for the timeout.

Note: If a modern SSH client refuses to connect to an older card with “no matching key exchange method found”, see our guide to ssh kexalgorithms for a safe, per-host fix.

Fix 3: Use the serial console

The NMC 2 guide documents a serial connection for local CLI access:

1. Connect the APC serial cable (part number 940-0299) from your computer to the card’s serial console port.
2. Open a terminal program such as PuTTY or Tera Term on that COM port with 9600 bps, 8 data bits, no parity, 1 stop bit, no flow control.
3. Press Enter, repeatedly if needed, until the User Name prompt appears.
4. Log in with an Administrator account and run reboot, as in Fix 2.
5. Type quit or exit to log off when you’re done.

Fix 4: Press the Reset button once

On the AP9630 and AP9631, the front-panel Reset button restarts the network management interface. The guide notes that this doesn’t affect the output power of the UPS.

Important: Press the button once. In APC’s lost-password procedure, a second press while the status LED flashes orange and green temporarily resets the user name and password to the defaults. Only do that on purpose, with a serial cable connected.

Wait for the card to finish restarting, then open its web page again.

How to stop it from happening again

On NMC 2 firmware, an administrator can change two settings:

• Session timeout per user: Configuration > Security > Local Users > Management, select the user name, then change Session Timeout (default 3 minutes, 1 to 60). Log off for the change to take effect.
• Allow Concurrent Logins: Configuration > Security > Session Management. With it enabled, up to eight web users, five CLI users and one serial user can be logged on at once.

Once you’re logged in, an administrator can also open Control > Security > Session Management to see who is logged on, from which interface and IP address, and use Terminate Session to end a stale one.

Ask everyone who uses the card to click Log Off instead of closing the tab.

If it still doesn’t work

• Check the address. Make sure you’re reaching the right card by IP address, and that it answers on the network.
• Look for something that stays logged in. A monitoring script or a session someone left open on another PC can keep taking the slot. On NMC 2 the Session Management screen shows the IP address of each session.
• Update the firmware. APC’s guide points to its download site for the latest NMC firmware; check the release notes for your card.
• Call for help. If the card won’t respond to the web, CLI or serial console after a Reset, contact APC/Schneider Electric support or your facilities team.

More hardware and network fixes are in PC Repairs and our computer repair tips. For faster work at the console, see the Command Prompt shortcuts guide.