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iPhone Cannot Connect to Mobile Data – How to Fix It 2026 Guide

Why Choose Keith Thomas

20 years of experience as a Senior Apple Support Specialist at Apple Computer UK HQ.

• Former Apple Computer UK Mac Support Specialist and Apple Authorised Service Provider background.

Established and Independent since 2010 for on‑site Apple Support Service – no call centres, no outsourcing, no hardware repairs. Over 25,000+ Apple problems resolved. Unique on-site Apple Support Service. backed up with Independent Apple Telephone Support Assistance.

• Trusted by home users, small businesses, and professionals across London and the South East UK.• Clear, honest, software‑only support. No Hardware Repairs. Expert Apple Consultancy Service.

On‑site iPhone and Mobile Network Support in London and the South East UK

What this page covers

This guide explains the most common reasons why an iPhone cannot connect to mobile data, the steps you can try yourself, and when it’s time to get professional on‑site help. It applies to:

• iPhone 17 / 17 Pro / 17 Pro Max / iPhone Air

• iPhone 16 / 16 Pro / 16 Pro Max

• iPhone 15 / 15 Pro

• iPhone 14 / 14 Pro

• iPhone 13 / 13 Pro

• iPhone 12 / 12 Pro

• iPhone SE (2nd and 3rd generation)

And all UK mobile networks including EE, O2, Vodafone, Three, Sky Mobile, BT Mobile, Virgin Media O2 and Tesco Mobile.

The most common mobile data problems

These are the issues Keith Thomas sees most often during on‑site visits:

• iPhone cannot connect to mobile data

• iPhone mobile data not working

• iPhone says “No Service”

• iPhone stuck on 3G or E

• iPhone not connecting to 4G or 5G

• iPhone mobile data not working after update

• iPhone mobile data not working after switching networks

• iPhone mobile data not working abroad

Quick checks you can do yourself

These steps solve around 50% of mobile data issues.

Check 1 – Restart the iPhone

Check 2 – Turn Airplane Mode off and on

Check 3 – Check mobile signal strength

Check 4 – Turn off Wi‑Fi Calling temporarily

Check 5 – Make sure Mobile Data is turned on

iPhone cannot connect to mobile data

This usually means:

• Network issue with your mobile provider

• Mobile data disabled in settings

• Temporary network congestion

Try:

• Restarting the iPhone

• Turning Airplane Mode off and on

• Checking Mobile Data settings

iPhone says “No Service”

This usually means:

• Network outage

• SIM activation issue

• Faulty network configuration

Try:

• Restarting the iPhone

• Removing and reinserting the SIM

• Checking for carrier settings updates

iPhone stuck on 3G or E

This usually means:

• Weak 4G/5G coverage

• Network congestion

• Incorrect network mode selected

Try:

• Settings → Mobile Data → Voice & Data → Select 4G or 5G

• Restarting the iPhone

• Moving to an area with better signal

iPhone not connecting to 4G or 5G

This usually means:

• 4G/5G disabled in settings

• Network not supporting 5G in your area

• SIM not provisioned for 5G

Try:

• Turning 4G/5G on in Mobile Data settings

• Restarting the iPhone

• Contacting your mobile provider

iPhone mobile data not working after update

This usually means:

• Network settings reset during update

• Carrier settings update required

• Temporary iOS bug

Try:

• Resetting network settings

• Checking for carrier settings updates

• Restarting the iPhone

iPhone mobile data not working after switching networks

This usually means:

• SIM not activated yet

• Porting delay (PAC code transfer)

• Incorrect APN settings

Try:

• Restarting the iPhone

• Turning Airplane Mode off and on

• Contacting your mobile provider

iPhone mobile data not working abroad

This usually means:

• Data roaming disabled

• Network not supporting roaming

• Temporary roaming network issue

Try:

• Turning on Data Roaming

• Restarting the iPhone

• Selecting a different network manually

When DIY stops working

You should get on‑site help if:

• Mobile data will not connect at all

• Mobile data works on another phone but not your iPhone

• Mobile data stopped working after an update

• Mobile data only works in certain locations

These issues usually require:

• iPhone network configuration repair

• Mobile provider diagnostics

• APN and carrier settings repair

• iPhone and iCloud network checks

On‑Site iPhone Support – London & South East UK

If your iPhone cannot connect to mobile data, Keith Thomas provides an often same‑day on‑site support service across:

• Central London

• West, North, South and East London

• Surrey

• Berkshire

• Hampshire

• Wiltshire

Keith Thomas is an Apple Support Specialist in:

• iPhone mobile data and network issues

• Apple Account and iCloud network configuration

• Mobile provider troubleshooting

• iPhone configuration and repair

Book on‑site help in London and the South East UK

If your iPhone cannot connect to mobile data, Keith Thomas can visit your home or office and get everything working again.

Keith Thomas – Apple Support Specialist

Established 2010 – Open 09:30–20:30, 7 Days

Contact Keith Thomas by Telephone: 07800 940756 or by Text to: 07800 940756, or simply complete an online website contact form 24/7