Xiaomi Wi-Fi Calling Greyed Out in Swansea

Xiaomi WiFi Calling Greyed Out? – UK Fix (2026)

If WiFi Calling (VoWiFi) is greyed out on your Xiaomi, Redmi or POCO phone, the problem is usually related to carrier compatibility, network settings, or IMS registration. This UK guide explains the most common fixes for EE, O2, Vodafone, Three and other networks.

Works For

  • ✔ Xiaomi 13 / 14 / 15 series
  • ✔ Xiaomi 13T / 14T
  • ✔ Xiaomi 11T / 12X
  • ✔ Redmi Note 11 / 12 / 13 / 14 series
  • ✔ POCO X5 / X6 / X7
  • ✔ POCO F series
  • ✔ HyperOS
  • ✔ MIUI 12.5 / 13 / 14

About this guide: We tested the most common Xiaomi VoWiFi problems reported by UK users and collected the fixes that work across HyperOS and MIUI devices.

WiFi Calling Greyed Out? Quick Fix

  • ✔ Enable VoLTE first – WiFi Calling often requires VoLTE (4G Calling) to be active.
  • ✔ Check carrier support – Contact your UK carrier to confirm they support VoWiFi on your device model.
  • ✔ Connect to WiFi – The option may remain greyed out until you're connected to a stable WiFi network.
  • ✔ Check IMS registration – Dial *#*#4636#*#* and check if IMS shows "Registered".
  • ✔ Enable VoWiFi with code – Dial *#*#869434#*#* in the Phone app to toggle VoWiFi on.
  • ✔ Reset network settings – Settings → Connection & sharing → Reset Wi-Fi, mobile & Bluetooth.

Quick Reference – Find Your Fix

ProblemMost Likely CauseFix
WiFi Calling option greyed outVoLTE disabled or no WiFi connectionEnable VoLTE; connect to WiFi
Option greyed out after HyperOS updateHyperOS reset or IMS registration issueUse engineering code; check IMS registration
Option visible but not workingCarrier provisioning or SIM issueContact carrier; update SIM
Option greyed out on EEDevice not on EE approved listCheck EE compatibility; contact EE
Option greyed out on O2Firmware compatibility or VoLTE profileCheck O2 support; enable VoLTE

Quick Answer

If WiFi Calling is greyed out on your Xiaomi, the most common causes are VoLTE being disabled, not being connected to WiFi, or IMS registration failure. Start by enabling VoLTE (4G Calling) in Settings → SIM cards & mobile networks, then connect to WiFi. If the option is still greyed out, dial *#*#869434#*#* to enable VoWiFi.

Before You Start

  • Enable VoLTE first – WiFi Calling often requires VoLTE (4G Calling) to be enabled. Go to Settings → SIM cards & mobile networks → Your SIM → Enable "Use VoLTE" or "4G Calling".
  • Connect to WiFi – The WiFi Calling option may remain greyed out until you're connected to a stable WiFi network.
  • Check carrier support – Your UK carrier must support VoWiFi on your specific Xiaomi model. Contact EE, O2, Vodafone, or Three to confirm.
  • Update your phone – Go to Settings → About phone → Check for updates. Software updates often fix connectivity issues.
  • Check your SIM region – Some imported Xiaomi models or unsupported regional firmware versions may have limited carrier feature support.

Why WiFi Calling Is Greyed Out on Xiaomi

Understanding why this happens helps you fix it correctly. In many UK Xiaomi cases, WiFi Calling appears only after the phone successfully registers IMS on the carrier network.

Phone-Related Causes

  • VoLTE disabled – On Xiaomi devices, VoWiFi and VoLTE features are often linked. If VoLTE is off, WiFi Calling may be greyed out.
  • No WiFi connection – The WiFi Calling option often only becomes active when you're connected to a WiFi network.
  • IMS registration failure – If IMS (IP Multimedia Subsystem) is not registered, VoWiFi won't work. Dial *#*#4636#*#* and check IMS Service Status.
  • HyperOS update issues – Some users have reported WiFi Calling options disappearing or becoming greyed out after HyperOS updates. A simple restart often resolves this.
  • Chinese ROM (CN) – Xiaomi phones with Chinese ROM may have limited VoWiFi support.
  • Dual SIM conflict – If you have two SIMs (e.g., EE on SIM1 and Vodafone on SIM2), IMS may not register on the non-preferred SIM.
  • Region setting mismatch – If your phone's region setting doesn't match your SIM's region, carrier features like VoWiFi may not appear.
  • Carrier configuration update pending – Sometimes carrier settings need to be updated manually. Check Settings → About phone → Carrier configuration.

Carrier-Related Causes

  • Carrier doesn't support your Xiaomi model – Each UK carrier maintains a list of approved devices for WiFi Calling. Even if the phone supports VoWiFi, the carrier may not have enabled it for your model.
  • Carrier provisioning required – Some carriers need to activate VoWiFi on your account before the option becomes active.
  • SIM card issues – Older SIM cards can sometimes cause VoWiFi provisioning issues.

Xiaomi WiFi Calling Greyed Out by UK Carrier

If your WiFi Calling option is greyed out, the issue may be specific to your UK carrier:

CarrierCommon ReasonFix
EEDevice not on approved listCheck EE compatibility; contact EE support
O2Firmware compatibility or VoLTE profileCheck O2 support; enable VoLTE; update firmware
VodafoneVoLTE profile issueCheck Vodafone device support; enable VoLTE
ThreeIMS provisioningContact Three to check IMS settings

UK MVNOs and WiFi Calling

If you're using a UK Mobile Virtual Network Operator (MVNO), WiFi Calling availability depends on the host network:

MVNOHost NetworkNotes
giffgaffO2Contact giffgaff support to confirm VoWiFi on your plan
SMARTYThreeDepends on Three's device compatibility
VOXIVodafoneCheck VOXI's supported device list
LebaraVodafoneContact Lebara support directly
Tesco MobileO2Check Tesco Mobile's device compatibility

Step-by-Step Fixes

Step 1: Enable VoLTE (4G Calling)

VoWiFi often requires VoLTE to be enabled. On many Xiaomi devices, these two features are linked.

  • Settings → SIM cards & mobile networks
  • Tap your carrier's SIM
  • Look for "Use VoLTE" or "4G Calling"
  • Ensure it's toggled ON

Visual Path: Settings → SIM cards & mobile networks → [Your carrier] → Use VoLTE → ON

Step 2: Connect to WiFi

The WiFi Calling option may remain greyed out until you're connected to a stable WiFi network.

  • Connect to a WiFi network with a stable internet connection
  • Check if the WiFi Calling option becomes active

Step 3: Enable VoWiFi via Engineering Code

On some Xiaomi devices, the WiFi Calling option is hidden behind a carrier compatibility check. This code may restore the option.

Important: This code does not add WiFi Calling support. It only removes Xiaomi's carrier check. Your UK network must still support VoWiFi on your exact model.

  1. Open the Phone app
  2. Dial *#*#869434#*#* (VoWiFi carrier check disable)
  3. You should see a message: "VoWiFi carrier check was disabled" or "VoWiFi carrier was disabled"
  4. Restart your phone
  5. Check Settings → SIM cards & mobile networks for the WiFi Calling option

Note: This code may reveal the WiFi Calling option on some devices, but it cannot add carrier support if your network does not officially support your Xiaomi model.

Step 4: Enable WiFi Calling in Settings

Once the option is available, enable it:

  1. Settings → SIM cards & mobile networks
  2. Tap your carrier's SIM
  3. Look for "Make calls using Wi-Fi", "WiFi Calling", or "VoWiFi"
  4. Toggle it ON

Visual Path: Settings → SIM cards & mobile networks → [Your carrier] → Make calls using Wi-Fi → ON

Step 5: Check IMS Registration Status

If WiFi Calling still doesn't work, IMS may not be registered. This is a common issue on Xiaomi devices.

  1. Open the Phone app
  2. Dial *#*#4636#*#*
  3. Tap Phone information
  4. Look for IMS Service Status or IMS Registration
  5. It should show Registered. If it shows Not Registered, VoWiFi won't work
  6. If IMS is not registered, restart your phone and check again

Step 6: Contact Your UK Carrier

If the option is still greyed out, contact your carrier to confirm they support WiFi Calling on your specific Xiaomi model.

  • EE – Call 150 or check the EE website for supported devices
  • O2 – Call 202 or check O2's support pages
  • Vodafone – Call 191 or check Vodafone's device support
  • Three – Call 333 or check Three's support pages
  • MVNOs (Giffgaff, Lebara, SMARTY, Tesco Mobile) – Contact customer support to confirm VoWiFi support

Step 7: Reset Network Settings

If other steps don't help, resetting network settings can clear any corrupted data.

  1. Settings → Connection & sharing
  2. Select Reset Wi-Fi, mobile & Bluetooth or Reset network settings
  3. Confirm the reset
  4. Restart your phone
  5. Re-enable WiFi Calling using the steps above

Step 8: Update HyperOS / MIUI

Xiaomi releases updates that fix connectivity issues. Some users have reported WiFi Calling issues resolving after a system update.

  1. Settings → About phone → Check for updates
  2. Install any available updates
  3. Restart your phone and test

Step 9: Check Dual SIM and Region Settings

If you're using dual SIMs or your region setting doesn't match your SIM, carrier features may not appear correctly.

  • Check region setting – Settings → Additional settings → Region. Set it to your actual location (e.g., UK).
  • Dual SIM conflict – If you have two SIMs, try removing one and testing WiFi Calling on the other.
  • Some imported Xiaomi models or unsupported regional firmware versions – These may have limited carrier feature support.

UK Carrier-Specific WiFi Calling Information

EE, O2, Vodafone and Three support WiFi Calling, but availability depends on your Xiaomi model, firmware version and account settings.

CarrierNotes
EEAvailability depends on Xiaomi model and EE compatibility list
O2Depends on supported device and account settings
VodafoneCheck supported device list
ThreeDepends on device compatibility
MVNOs (Giffgaff, Lebara, SMARTY, Tesco)Varies by MVNO and plan – contact customer support directly

What to Do If WiFi Calling Still Doesn't Work

If WiFi Calling is still greyed out or not working after completing all steps:

  • Test in an area with poor cellular coverage – WiFi Calling activates when cellular signal is weak
  • Test with another VoWiFi-enabled device – This helps identify if the issue is with your phone or your carrier
  • Test with another SIM card – Try another VoWiFi-enabled SIM to rule out carrier issues

Contact Xiaomi UK Support

If WiFi Calling still doesn't work after completing all steps, contact Xiaomi UK Support:

  • Xiaomi UK Support website – Official support portal for UK customers
  • Feedback app – Settings → Services & feedback
  • Xiaomi Community – Post in official Xiaomi community forums, including UK-specific threads

Final Verdict

If your Xiaomi WiFi Calling is greyed out, start by enabling VoLTE (4G Calling) and connecting to a stable WiFi network. If the option is still greyed out, use the engineering code *#*#869434#*#* to enable VoWiFi. Check IMS registration status with *#*#4636#*#*. If the option still doesn't work, contact your UK carrier to confirm support for your device model. If EE or O2 works on another phone but not on Xiaomi, the problem is usually device certification rather than your SIM.

Quick summary:

  • Option greyed out → Enable VoLTE; connect to WiFi
  • Option still greyed out → Use engineering code *#*#869434#*#*
  • Not working after enabling → Check IMS registration with *#*#4636#*#*
  • IMS shows Not Registered → Restart phone; update HyperOS; check region settings
  • Still not working → Contact carrier; check ROM version
  • EE only issue → Check EE's approved device list
  • O2 only issue → Check VoLTE provisioning and firmware compatibility

Frequently Asked Questions

Why is WiFi Calling greyed out on my Xiaomi?

Common causes include: VoLTE disabled, no WiFi connection, IMS registration failure, or your carrier doesn't support VoWiFi on your specific Xiaomi model.

How do I enable WiFi Calling on Xiaomi if it's greyed out?

Enable VoLTE first, connect to WiFi, then dial *#*#869434#*#* to enable VoWiFi. After that, go to Settings → SIM cards & mobile networks → Your SIM → Enable "Make calls using Wi-Fi".

What does *#*#869434#*#* do on Xiaomi?

This engineering code toggles Xiaomi's carrier compatibility check for VoWiFi. It only removes Xiaomi's carrier check—it does not add WiFi Calling support. Your UK carrier must still support VoWiFi on your exact model.

What is IMS registration on Xiaomi?

IMS (IP Multimedia Subsystem) registration is required for VoWiFi and VoLTE to work. If IMS shows "Not Registered," VoWiFi won't work. Dial *#*#4636#*#* and check IMS Service Status.

Why does Xiaomi WiFi Calling work on Vodafone but not EE?

Different UK carriers maintain different approved device lists. EE may not have certified your specific Xiaomi model for WiFi Calling, while Vodafone may have. Check each carrier's compatibility list.

Why does my Xiaomi show VoWiFi icon but calls still use mobile network?

WiFi Calling activates only when cellular signal is weak. If you have strong 4G/5G signal, the phone will prefer the cellular network. Test in an area with poor cellular coverage to see if WiFi Calling activates.

Does WiFi Calling work on UK Xiaomi devices?

Yes, if you have Global ROM and your UK carrier supports VoWiFi on your specific Xiaomi model. EE, O2, Vodafone, and Three all offer VoWiFi, but not every Xiaomi model is approved.

Why is WiFi Calling greyed out after HyperOS update?

HyperOS updates can sometimes reset network settings or cause IMS registration issues. Try restarting your phone, re-enabling VoLTE, and dialling the engineering code *#*#869434#*#*.

Do these fixes work on UK Xiaomi devices?

Most steps are similar across Xiaomi, Redmi and POCO devices, but menu names may vary depending on your HyperOS or MIUI version.

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