DP750 account status falsely shows red "SIP Registration: NO" after inactivity on admin web interface


I’m seeing an odd bug.

I am running a Grandstream DP750 (Part Number 9610003817A (C1)) with two DP720 handsets. I’m SIP registered to toronto1.voip.ms and have applied the settings from https://wiki.voip.ms/w/index.php?title=Grandstream_DP750/DP720&stable=0 per my providers recommendation.

The phones work - no issues there. It’s just that the web interface at is showing weird “account status”. I sign onto the admin webpage and everything is pretty and green, “SIP Registration: YES”. I wander off and do something else (or, worse yet, “suspend” my PC) with the tab still open. When I return, I see bright red “SIP Registration: NO” on every virtual line.

I’m still registered to Swiftvox (voip.ms) and the phones are still all working. I can click through the various status tabs on the admin page and it’ll say that the handsets are still connected to the base but show a big red NO for the SIP registration to my upstream provider. If I force a web browser refresh, then it kicks me out and forces me back to the login screen. If I log out and back in, everything goes back to green “SIP Registration: YES”.

It would seem that my login to the admin webpage on the DP750 is timing out or expiring somehow but, instead of being honest enough to say so, whatever JS you’re running in my browser is instead falsely reporting that I’ve lost SIP registration on every virtual line… and this with the phones all still up and working.

I’m running the current firmware ( on this system, which is currently configured with two DP720 handsets and two SIP registrations to different accounts on the same provider (toronto1.voip.ms), ringing all extensions “parallel” on inbound calls as if it were a plain two-line “key system”. Nothing unusual, but leaving the console and coming back to bright red “SIP Registration: NO” on every line is disconcerting - primarily because this is wasting my time troubleshooting a SIP registration issue which in all probability does not exist.

Weirder yet, I happen to have two tabs open to the same DP750 base from the same web browser. One web admin session has timed out, another (in the other tab) has not. I toggle between these two open browser tabs - one is claiming that every line has lost SIP registration to toronto1.voip.ms (big red “NO”) and the other is claiming that everything is fine (big green “YES”) for the same SIP registrations on the same hardware.

This has to be a bug. Both conditions can’t be simultaneously true.

It looks very real… both tabs even pretend to be refreshing automatically every minute or so. But it’s not.