APC network cards – or the NIC of many APC devices like UPS and A/C – possibly even NetBotz (APC – aka. Schneider Eletric) tend to have an issue that the system is telling you in the browser that there is already a session active.
The reason is that they tend to keep the session online forever, if you don’t click on logoff before you close your browser etc.
What you will see is an error like this after you entered your valid credentials:
|Someone is currently logged into the APC Management Web Server.
Please try again late
It is actually pretty easy to bypass this – you either use TELNET or SSH to logon to the system with the same credentials and then simply logout there.
While doing so – you logoff the user and you will be able to logon again.