Microsoft 365 Business Voice with phone system and calling plan issue

Occasional Contributor



I am trying to set up a trial of MSFT 365 Business Voice for my company. Currently we are using 8x8 for PSTN calls but we want to switch to a MSFT only environment. Our tenant is located in the US, but one of our offices is located in Croatia. 


I got the trial licenses for Business Voice, Phone System and Domestic Calling plan. I've got a phone number assigned to one user successfully, also assigned him one of each of the trial licenses: Business Voice trial, Phone System Trial and Domestic Calling Plan trial.

After doing all that, the user is still unreachable by phone from a regular 8x8 number which is located in the US. The user with the phone number is not reachable ("Couldn't complete the call, check you are using the correct number format...") from any phone number nor is he able to make any calls to anyone.


If I do a regular Teams call to the number, the user can receive it. Our goal is to make the number reachable from any phone system, not just from Teams. I believe what we want is PSTN capability for the number, but do correct me if I am wrong.


What else do I need to set up for the phone system to start working like intended?

11 Replies

@NSimpraga Hi,


Just to make you aware that Calling Plans are not available in Croatia. E.g. You cannot use Microsoft to provide a Croatian number so before you continue, you may want to bear that in mind.

The alternative is Direct Routing where you use your own SIP Trunk with a Session Border Controller. That then allows you to use your existing Croatian numbers to deliver calls into Teams.


Another alternative is to use a hosted provider, not Microsoft who can host the SBC and SIP Trunks for you.


Aside from that, what you have done below seems correct. Does the user have the Calls tab and see a number pad?  Does the telephone number of what you're calling appear on that number pad?



Hi @NSimpraga,

Has this user ever been configured for 8x8 and direct routing previously in the past? If so they probably have an online voice routing policy assigned when it was set up

You will want to remove any of the old configuration on that particular user. Can you confirm that has been done? This may be causing the issue

Let me know

Best, Chris

I am aware that MSFT can't provide CRO numbers to us, that is why I selected US as our location since our tenant's location is USA. Our main office is also located in the US.

The first user I mentioned got a US phone number assigned correctly which I mentioned already. I am just confused as to why it is not reachable from regular US phone numbers.

Regarding 8x8, it is not in any way associated with this phone number. This phone number was provisioned directly from the Teams admin center via the Order method.

best response confirmed by NSimpraga (Occasional Contributor)
Hmm ok that's a great clarification. Is the users location set as Croatia when you assigned a licence? Can you check?

Best, Chris

Hm so the Usage Location property of the user in Azure AD is set to Croatia, but the Location field in the Teams admin center is set to a US location. Screenshot below, the first number is the user we are talking about.



Do you want to say that the Usage Location property from AAD has to be set to USA also?


I think it would be worth setting up a completely new user with a usage location in the US, emergency address of the US and assigning them the number and see if it works.

Croatia is not in calling plans currently - usage location is linked to what services work. I don't know whether this will resolve it, it's just a hunch and worth trying out

Let me know how you get on

Best, Chris

@Christopher Hoard Just got off from the first successful call! :) Usage Location was the issue, it has to be set to United States in order to work. Thanks so much!


One issue - the calls (when they are being received by the assigned numbers) are being received through Skype For Business, not through Teams.


I can make calls from Teams using those numbers, but when the same user (phone number) is dialed, it is not receiving the calls through Teams but through SFB. If the user does not have SFB either on his PC or Mobile, the phone rings from the callers perspective (you can hear the ringing) but the receiving user's Teams is not picking up the call. After the call hangs, the user gets an email for a missed call. 

So basically, if you don't have SFB installed, you can't receive calls


Since SFB is retiring 2021, this does not make sense at all. Is this intended behavior? Can this be changed so the users get calls on Teams?

OK, see if the user is set to Teams Only in the Teams Admin Centre. If not, set it to Teams Only

Best, Chris

@Christopher Hoard  Hmm I can't seem to find that exact option in the Teams Admin Centre, can you specify which option is that exactly? Thanks!

Alright, rushed a bit with the question, found the option under Coexistence mode. Turned it to Teams-only and now it works as intended. Thank you for the help!


On another note, I am looking to buy the actual non-trial licenses now. I am a bit confused with pricing though. For the trial, I had to get the Business Voice, Phone System and Calling plan TRIAL licenses, assign them all to the users and only then would the system work.


For the regular Business Voice licenses a promo is currently available for us and it says it includes the Phone System and Domestic Calling plan licenses all for only 15$, which sounds REALLY cheap. Screenshots below.




Why did I have to get the separate licenses (Phone System, Calling plan, business voice) for the trial if it is actually included in the Business Voice license itself?