Deploying Microsoft Teams Phone is one of the fastest ways to modernize voice, but moving fast doesn’t mean skipping the fundamentals.
IT teams often dive into rollout planning with the best intentions, only to hit roadblocks that frustrate users, overload support, or impact ROI.
These issues aren’t usually caused by the technology itself, but by gaps in preparation, misaligned expectations, or avoidable oversights.
From mismatched licensing and neglected call flows to porting delays and forgotten E911 setup, even small mistakes can ripple across the organization. Fortunately, they’re also easy to prevent if you know what to look for.
Based on lessons from real-world deployments, this guide breaks down eight of the most common mistakes IT teams make when implementing Microsoft Teams Phone and how to avoid them with clear, actionable steps.
1. Skipping a network readiness assessment
One of the most common (and costly) mistakes IT teams make is assuming their existing network is ready for voice.
But even high-speed internet doesn’t guarantee call quality. Without a proper assessment, you risk call jitter, packet loss, dropped connections, and a surge of complaints from users who expect Teams Phone to “just work.”
What typically goes wrong
- Voice traffic competes with other workloads, leading to poor quality
- Sites with inconsistent bandwidth or legacy switches become hotspots for call issues
- QoS isn’t enabled, so Teams traffic gets treated like any other data
How to avoid it
Before any rollout, run a proper network assessment. Use Microsoft’s Network Planner to estimate expected voice usage by location.
Implement QoS tagging to prioritize real-time traffic like audio and video. Segment guest Wi-Fi traffic from internal voice networks, and consider SD-WAN if your business spans multiple sites.
This step is about building a strong foundation. Voice is sensitive, and your users won’t tolerate quality issues that could have been prevented.
2. Choosing the wrong PSTN connectivity option
Microsoft Teams Phone supports several ways to connect to the PSTN, including Calling Plans, Direct Routing, and Operator Connect. Each has pros and cons, but many IT teams default to what’s familiar or easiest to activate without considering long-term scalability, complexity, or administrative overhead.
What typically goes wrong
- Organizations choose Microsoft Calling Plans but quickly outgrow their limitations
- Internal IT ends up managing Session Border Controllers (SBCs) with Direct Routing and struggles with support or uptime
- Connectivity decisions are made without considering geographic reach, compliance needs, or carrier SLAs
How to avoid it
Start by understanding the tradeoffs. Microsoft Calling Plans are good for small, centralized teams, but often fall short for global deployments.
Direct Routing offers control, but comes with more maintenance.
For most mid-size and enterprise deployments, Operator Connect offers the best of both worlds: direct integration with Microsoft, no infrastructure to manage, and support from a certified provider like Momentum.
Not sure what’s best for your organization? Read our ultimate guide to migrating from Direct Routing or Microsoft Calling Plans to learn more.
3. Underestimating the complexity of number porting
Porting phone numbers into Microsoft Teams Phone is not a one-click task. It involves coordination between carriers, regulatory compliance in some regions, and meticulous data accuracy.
When overlooked, it’s one of the easiest ways to create disruptions that frustrate users and delay go-live.
What typically goes wrong
- Numbers are missing from the porting request or are incorrectly mapped to users
- Regional carriers impose restrictions or delays, especially for international numbers
- Account information doesn’t match carrier records, causing rejections
- Cutover timelines aren’t aligned with license assignment or device readiness
How to avoid it
Start early. Build a complete inventory of all numbers in use, including direct dials, shared lines, and special-purpose numbers like fax or emergency endpoints. Confirm which users need voice service and map each number to its destination.
Validate your records with your current provider to catch any discrepancies before submission. For smoother execution, partner with an Operator Connect provider like Momentum that manages the porting process end-to-end, ensuring correct timing, regulatory compliance, and zero service disruption.
4. Failing to map call flows before go-live
A Teams Phone rollout replaces hardware while also redefining how calls move through your organization. If call flows aren’t mapped and tested before go-live, users can’t reach the right person, customers hit dead ends, and support teams are flooded with complaints.
What typically goes wrong
- No plan for auto attendants or mainline greetings
- Call queues aren’t configured, or lack logic like longest idle or round robin
- Overflow rules, after-hours routing, or voicemail destinations are missing
- Key departments or individuals are unreachable during peak hours
How to avoid it
Treat call flow planning as a core part of your deployment. Start by documenting all existing call paths, including how external calls reach support, sales, or reception. Design menu prompts, queue logic, and failover rules intentionally, not reactively.
Before launch, walk through user scenarios to validate every call path. For example: “What happens if someone calls after 6 p.m.? Who answers if no one is available in support?” You can use Microsoft’s Teams admin center to build these flows in advance.
Need help thinking it through? Use our Teams Phone readiness checklist to ensure every routing detail is covered before go-live. It’s the fastest way to pressure test your plan and avoid surprises on day one.
5. Overlooking E911 configuration
Emergency calling in Microsoft Teams requires more than enabling a feature. For most companies, it depends on accurate user location mapping, tested routing, and ongoing maintenance. Skipping or rushing this step can leave you non-compliant, or worse, unable to route calls to the correct emergency services.
What typically goes wrong
- Emergency addresses are missing or outdated for key users and locations
- Subnet mapping isn’t configured, making it hard to locate remote users
- Emergency calls are misrouted to the wrong Public Safety Answering Point (PSAP)
- No testing is done before go-live to validate the emergency call path
How to avoid it
Start by assigning emergency addresses to users based on their primary work location or subnet. Configure dynamic E911 settings for hybrid or mobile employees. If you’re using Operator Connect, coordinate with your provider to test call routing and confirm it reaches the correct PSAP.
Finally, don’t treat this as a one-time task. Review and audit your E911 configurations regularly, especially when offices change, users move, or your network evolves. This supports compliance while protecting your people.
6. Not training users on Teams Phone features
Many employees are comfortable using Teams for chat and meetings, but calling introduces a new set of workflows. If users don’t know how to transfer a call, check voicemail, or use the mobile app, you’ll see adoption stall and support tickets spike.
What typically goes wrong
- Users aren’t confident placing or managing calls in the new system
- Common actions like forwarding or transferring create confusion
- Help desk volume surges after go-live due to basic usage questions
- Advanced features like voicemail transcription go unused
How to avoid it
Don’t wait until launch to introduce Teams Phone. Create short, role-specific training for common scenarios: how to make and receive calls, use voicemail, transfer to a colleague, or switch devices mid-call.
Use a mix of formats like video walkthroughs, quick-reference PDFs, and short virtual sessions. Share everything in a Teams channel or a SharePoint site that users already visit. You can even add a “Teams Calling Tips” tab with how-to guides and FAQs.
The goal isn’t to train everyone all at once. The focus should be on providing users with just enough to succeed without overwhelming them.
7. Delaying Teams-certified device rollout
Your network might be ready and your Teams Phone setup flawless, but call quality will suffer if users are stuck with old, unsupported, or inconsistent hardware. Waiting until after go-live to standardize devices creates a fragmented experience and piles on unnecessary support work.
What typically goes wrong
- Users rely on built-in laptop mics or consumer-grade Bluetooth headsets
- Echo, background noise, and dropped audio lead to poor call perception
- IT teams struggle to troubleshoot when endpoints vary widely
- Device issues get blamed on the Teams Phone platform
How to avoid it
Standardize early. Choose Microsoft Teams-certified headsets, speakerphones, or desk phones for each user group, especially for call-heavy teams like support or sales. Certified devices are tested for compatibility, firmware support, and optimal call performance.
Roll them out before go-live so users can test, adjust, and get comfortable. Prioritize execs and frontline users who set the tone for adoption.
Need help deciding which devices work best by role or location? Read our Ultimate guide to Microsoft Teams Phone certified devices.
8. Going live without support from a certified provider
Rolling out Microsoft Teams Phone can stretch internal IT thin. Between number porting, E911 setup, device deployment, call flow configuration, and user support, it’s easy for critical details to get missed, especially without prior experience handling telecom transitions.
What typically goes wrong
- Porting delays, routing issues, or emergency call misconfigurations go unnoticed until after launch
- IT gets stuck managing infrastructure they didn’t plan for, like SBCs or dial plans
- Project timelines slip due to unclear roles, missed steps, or lack of support
- There’s no clear escalation path when something breaks during rollout
How to avoid it
Work with a certified Operator Connect provider like Momentum from the start. We handle everything from number provisioning and porting to call routing, E911 compliance, and user readiness. Our direct integration with Microsoft ensures your deployment stays aligned with best practices. Plus, our team is on-call 24/7 during and after launch.
You get one shot at making Teams Phone a seamless upgrade. Don’t go it alone. Find the right partner to ensure a seamless migration.
Eliminate risk, reduce effort, and get voice right the first time
Microsoft Teams Phone has the potential to unify your communication stack, reduce overhead, and simplify collaboration, but only if the rollout is done right.
Skipping critical steps or underestimating complexity can quickly turn a strategic win into an IT nightmare.
Avoiding the mistakes we’ve outlined helps ensure a smoother deployment, fewer surprises, and better adoption from day one.
Momentum helps you get there with confidence. As a certified Operator Connect provider, we manage the heavy lifting: from porting and call flow design to compliance and live support.
Ready to roll out Microsoft Teams Calling with confidence? Talk to Momentum about Operator Connect for your business.
