Issue after only Virtual Multi-Purpose Key (VMPK) #6 is set, breaks all functionality of the phone and cannot call


When we set VMPK #6 on any of the phones, it breaks all functionality of the phone and cannot call or anything.

If we reset the #6 multi-purpose key to none, phone works fine again. It’s happening on all phones and its only that particular key (#6). all others can be set using BLF to any extension with no problem.

any ideas what could be causing this?


You need at least 1 x sip account programmed as a key on the phone or it will not be able to dial/receive a call. Are you setting all vpmk’s to something other for the first 2 ?


I only have 1 sip account at the moment and it’s what I set to each key, Account 1. However, whenever I set the same details(BLF on any extension) on #6, the phone stops working and we cannot call out, extensions or anything. I can set any other key just fine. It’s a weird issue. I’m setting these keys directly on the phones, not via zero config. I could not use zero config without issues. So been setting them manually on each phone.
Thanks for your help!


You need to have the first set of keys set for that handsets own extension else it will exhibit the same problem you are experiencing.

Take a picture of the handset how you have configured it and post here or pm me with it.


Yep, I have Account 1 SIP account setup on the phone and it calls out and works fine when I reset(disable) vpmk 6. All vpmks are being set to just account 1, but for w.e reason only #6 breaks the phone connection, and when reset works fine again. I will get you those screenshots of my setup soon when next time on-site. thanks for your help!


My specific question was about how the extension account was applied to the keys. If no account mapped to the handsets keys will exhibit the issue you are noting.


i’m setting only Account 1 to all these keys.
However, this is my current configuration that works fine.

So issue is, If I set vmpk #6 the same as the other keys (Account 1, BLF, Value set to extension), phone stops working and cannot call or receive calls. If I reset it back to how you see in the screenshots using Reset button (Default, Account 6, no value), then it starts working again. This is a weird issue and I can set all the other keys just fine.
Let me know what you find. I hope we can get this resolved. Thank you!!


Account status


Account Settings


Apparently I’m not the only one with this issue…


Hi Ralph,

it does not seem to be a bug / problem in the eyes of Grandstream. They say that you need on available line per phone purpose - so for just calling / being called you need one line. If you like to do a conference using the conference button or an un-/attended transfer you’ll need another (free) line. For every more call (conference with three or more participants) or being able to hold lines and call other lines you’ll need sufficient lines.
This is ok and no problem for me. What I do not understand: Those free lines need to be in the first colum of the screens VPKs. It is not possible to have them on the second page of the screen nor on the right side of the screen. IMHO the software of the phone should be able to automatically switch pages and use the first possible free VPK.
But whatsoever - at the moment we’ll need to do it this way and have a free VPK in the first column per line you want to use. For my setting I use two free VPK on the left side.
I hope this helps.


Ralph, the first and second VPMK need to be the account extension key, not programmed as a BLF.

As soon as you programme all of the keys on the handset as blf or other, you are removing the capacity for the telephone to be able to have Call pathways.

This is normal behaviour for the telephone as it does not have any line / call keys outside of the VPMK keys.

SO to fix your issue, try it again by removing VPMK 1 and 2 and making those the extension 1000, then add the rest as what ever you want else the handset will not work as a telephone, it will become a glorified BLF monitor.


OK I will try that and report back. Thanks for the help!