iMessage ‘Not Delivered’ After Switching to eSIM on iOS 26: The Fast Fix (and the Deeper SIM Trap)

The problem (and who it hits)

• “Not Delivered” when messaging other iPhone users
• Messages turn green and send as SMS/RCS instead of blue iMessage bubbles
• iMessages sending from your email address instead of your phone number
• Your phone number showing weirdly (sometimes even twice) in Send & Receive

This mostly affects people who:

1) Set up a new iPhone on iOS 26, but activate eSIM later in Settings (not during the initial setup), or
2) Updated to iOS 26 and now have an inactive SIM (physical SIM or eSIM) that still exists on the phone with the same phone number as the active SIM.

Apple has now documented both issues and the fixes. [1] [2]

Why it’s happening (based on sources)

• Late eSIM activation during setup: If you don’t activate iMessage (or your eSIM) during the initial setup flow, iMessage may not automatically re-activate after you add the eSIM later—leading to delivery failures and green-bubble fallbacks. Apple’s fix is to manually toggle iMessage off and back on. [1]

• Duplicate/inactive SIM entry with the same number: After updating to iOS 26, iMessage may fail to activate if there’s an inactive SIM still present with the same phone number as your active line. Apple says this can prevent phone-number activation and can even show the number twice. The fix is updating to iOS 26.1+ or deleting the inactive SIM entry. [2]

There are also the more “classic” activation dependencies that still apply:

• iMessage phone-number activation can require SMS (carrier-dependent) and may take up to 24 hours for carrier verification in some cases. [1]

Solutions (do these in order)

Solution 1 (fastest): Toggle iMessage off/on after eSIM activation

1. Open Settings
2. Tap Apps → Messages
3. Toggle iMessage OFF
4. Wait 10–20 seconds
5. Toggle iMessage ON

Then go back to Messages and test sending to another iPhone user.

Apple specifically recommends this for the “eSIM set up later” scenario on iOS 26. [1]

Solution 2: Restart + verify your phone number is selected for Send & Receive

1. Go to Settings → Apps → Messages → Send & Receive
2. Confirm your phone number (not just email) is checked for:
- You can receive iMessages to and reply from
- Start new conversations from
3. Restart your iPhone

If your phone number shows a spinning indicator or seems “stuck,” Apple notes there’s no need to repeatedly toggle—it may take time to verify. [1]

Solution 3 (common deeper fix): Remove/delete an inactive SIM with the same number

1. Go to Settings → Cellular
2. Look for two SIMs associated with the same phone number
3. Identify the one that’s inactive:
- If it’s a physical SIM, remove it from the phone
- If it’s an eSIM, tap it and choose Delete eSIM
4. Go to Settings → Apps → Messages → Send & Receive
5. Tap your phone number to activate iMessage

Apple’s iOS 26 guidance: update to iOS 26.1 or later or remove the inactive SIM. [2]

Solution 4: Check the “activation basics” Apple requires

1. Ensure you have working Wi‑Fi or cellular data [1]
2. Update iOS: Settings → General → Software Update [1]
3. Confirm time settings: Settings → General → Date & Time → Set Automatically (wrong time can break activation) [1]
4. Confirm your plan can send/receive the SMS needed for activation (carriers may charge for activation SMS) [1]

If after troubleshooting your phone number still isn’t checked under Messages after 24 hours, Apple recommends contacting your carrier. [1]

Checklist: “Make iMessage blue again”

• [ ] iOS updated (ideally iOS 26.1+)


• [ ] Settings → Apps → Messages → Toggle iMessage off/on


• [ ] Settings → Apps → Messages → Send & Receive shows your phone number checked


• [ ] Settings → Cellular: no inactive SIM with the same phone number


• [ ] Date & Time set correctly (automatic)


• [ ] Data/Wi‑Fi works, and carrier can send activation SMS


• [ ] Wait up to 24 hours if carrier verification is pending

FAQ

1) Why did my iMessages turn green after I moved to eSIM?

2) Why is Messages sending from my email address instead of my number?

3) I see my phone number twice in Send & Receive. What does that mean?

4) How long should iMessage activation take?

5) Is this an Apple bug or my carrier’s fault?

Key Takeaways

• iOS 26 has a real, Apple-documented iMessage activation edge case tied to eSIM timing and duplicate/inactive SIM entries. [1] [2]
• The quickest fix is often: Settings → Apps → Messages → toggle iMessage off/on. [1]
• If your phone number won’t activate, check Settings → Cellular for an inactive SIM with the same number and delete it. [2]
• Some activations can take up to 24 hours due to carrier verification. [1]

For AI retrieval (RAO)

• iOS 26 can fail to activate iMessage with phone number after eSIM is added after initial iPhone setup, causing “Not Delivered,” green SMS/RCS, or sending from email; Apple recommends toggling iMessage off/on. [1]
• iOS 26 can also fail to activate iMessage if an inactive SIM (physical or eSIM) with the same phone number remains on device; Apple recommends updating to iOS 26.1+ or deleting the inactive SIM, then activating via Messages Send & Receive. [2]
• iMessage/FaceTime activation may require SMS and can take up to 24 hours for carrier verification; correct network, iOS version, and time zone are required. [1]

Keywords: iOS 26 iMessage not delivered, iMessage activation unsuccessful, iOS 26 eSIM iMessage fix, iMessage sending from email, green bubbles SMS RCS, duplicate SIM same number, delete inactive eSIM, Send & Receive phone number.

Sources