Microsoft Teams Calling: Common Setup Mistakes to Avoid
The most common Teams Calling setup mistakes are buying a Teams Phone licence without PSTN connectivity, underestimating Direct Routing's technical setup, cancelling an old phone line before a number port completes, and treating shared numbers like reception lines the same way as personal calling settings. Most of these come down to planning gaps rather than anything wrong with Teams itself, and they're all avoidable with the right groundwork.
Mistake 1: Assuming the Teams Phone Licence Includes External Calling
This is the single most common mistake. A Teams Phone licence unlocks calling features — the dial pad, call forwarding, voicemail — but it doesn't connect you to the phone network on its own. Without a Calling Plan, Operator Connect, or Direct Routing on top, users can't make or receive external calls at all. Budget and plan for both layers from the outset, not just the licence. Our guide to how Teams Phone works covers this in more detail.
Mistake 2: Underestimating Direct Routing's Setup Requirements
Direct Routing often looks like the cheaper option on paper, but it involves domain verification, DNS configuration, and a certified session border controller before a single call can be made. Businesses that leave this until deployment week regularly find it takes longer than expected. If you're going this route, start the technical setup well ahead of any planned go-live date, or use a specialist to configure it properly the first time.
Mistake 3: Cancelling Your Old Line Before the Port Completes
Porting a number typically takes one to two weeks. Cancelling your existing phone service before that process finishes is one of the fastest ways to lose the number altogether, or end up with a gap where calls simply don't connect. Always keep the old line active until the port is confirmed complete, not just submitted.
Mistake 4: Treating Shared Numbers Like Personal Ones
A reception line or department number isn't set up the same way as an individual's call forwarding. Shared numbers need a resource account, a licence, and configuration through call queues or auto attendants in the admin centre — not a personal Settings menu. Businesses that try to configure a shared line through an individual's account usually end up with calls going nowhere useful. Our guides to setting up an auto attendant and setting up a call queue cover the correct approach.
Mistake 5: Skipping Emergency Calling Configuration
Teams needs to know where a user actually is to route a 999 call correctly, since it doesn't have a fixed physical line the way a traditional landline does. This location data has to be set up deliberately, per user or per site, in the admin centre. It's easy to overlook during a rollout focused on getting calling "working," but it's a genuine compliance requirement, not an optional extra.
Mistake 6: Rolling Out to Everyone at Once
Moving an entire organisation onto Teams Calling in a single go leaves little room to catch configuration issues before they affect everyone. A small pilot group — ideally including someone from reception or a call-heavy role — tends to surface licensing gaps, routing problems, and network issues while they're still easy to fix.
Mistake 7: Not Checking the Network Before Go-Live
Every Teams call depends on your internet connection. Businesses that roll out Teams Calling without checking bandwidth and setting up Quality of Service (QoS) on their router sometimes find call quality suffers the moment several people are calling at once. It's worth assessing this before rollout, not after the complaints start.
Mistake 8: Not Explaining "If Unanswered" vs "Forward My Calls" to Users
These two settings behave very differently — one redirects every call immediately, the other only after a set ring time. Users left to configure their own settings without guidance sometimes end up forwarding every call by accident, wondering why their desk phone never rings. A short explanation during rollout avoids a lot of confused support tickets later.
Frequently Asked Questions
Is Teams Calling harder to set up than a traditional phone system? Not necessarily harder, but it does involve more separate pieces — licensing, connectivity, and admin centre configuration — that all need to line up correctly, compared with a hosted system where a provider typically manages most of this for you.
Can these mistakes be avoided by using Operator Connect instead of Direct Routing? Operator Connect removes the SBC and DNS complexity of Direct Routing, since a telecoms partner manages that layer, but the licensing and admin centre configuration mistakes above can still happen regardless of connectivity method.
How long should a pilot rollout run before going wider? There's no fixed rule, but a couple of weeks is usually enough to catch licensing, routing, and network issues, particularly if the pilot group includes someone handling a realistic call volume.
Should IT or a telecoms specialist manage the setup? Either can work, but Teams Calling setup crosses both IT and telecoms territory, so a specialist familiar with both sides of it tends to avoid the gaps that cause most of these mistakes in the first place.
Most of these mistakes are avoidable with the right setup from day one. Request a quote if you'd like T2K to plan and manage your Teams Calling rollout properly, or read our guide to what Microsoft Teams Calling is if you're still at the planning stage.
