The 60-second answer
A QR code failure happens before the eSIM exists on your phone, which makes it a different problem from an installed eSIM with no signal. The four causes are: the code has already been used, you are scanning it on the same screen you need to scan with, the camera cannot resolve the image, or the phone has no internet to complete the download. Every provider that issues a QR code also issues the same details in text form — so if scanning will not work, you can almost always type the plan in by hand instead.
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What actually went wrong
| What you see | Cause | Fix |
|---|---|---|
| Camera will not recognise the code | Code on the same device, screen too dim, image too small | Second screen, raise brightness, or enter details manually |
| "Unable to Add Cellular Plan" | No internet, or the download server was unreachable | Connect to stable Wi-Fi and retry |
| "This code is no longer valid" | Already installed once — most codes are single-use | Contact your provider for a re-issue |
| "Cellular Plan Cannot Be Added" | Phone is carrier-locked | Check Carrier Lock status |
| Scans, then nothing happens | Install started but stalled on a slow connection | Restart, reconnect to Wi-Fi, retry once |
Install it manually instead
This is the fallback that solves most QR problems outright, and it is worth knowing before you need it. Your activation email contains an SM-DP+ address and an activation code — the exact same information the QR code encodes, just as text you can type.
Open your activation email
Find the SM-DP+ Address and the Activation Code. They are the text equivalent of the QR image; some providers label them "Address" and "Code".
Start adding an eSIM
iPhone: Settings → Cellular → Add eSIM → Use QR Code. Android: Settings → Network & Internet → SIMs → Add eSIM.
Choose manual entry
iPhone: tap "Enter Details Manually" below the camera viewfinder. Android: tap "Need help?" or "Enter it manually", depending on the version.
Type the details exactly
Enter the SM-DP+ address and activation code precisely as written — no trailing spaces, and watch for confusion between the digit 0 and the letter O. Copy and paste if you can.
Wait on Wi-Fi
Tap Next and stay on Wi-Fi. The profile downloads in roughly 10–30 seconds. Do not background the app while it runs.
Label and set your data line
Give it a recognisable label, keep your home SIM for calls, and set the new eSIM as your Cellular Data line.
If the code was already used
Most travel eSIM QR codes work exactly once. Installing, then deleting, then attempting to reinstall from the same code will fail — the code is spent even though the plan may still have data on it. This is an industry-wide fraud-prevention measure rather than a quirk of any one provider.
The fix is a re-issue from your provider, which most will do for a plan that was never actually used. Contact us with your order reference if it was a Flysimio plan — and see deleting an eSIM for why turning a line off is safer than removing it.
Do this before you fly
- Install at home, on Wi-Fi, with a second screen available. Every QR problem is easier to solve before you are standing in an arrivals hall.
- Screenshot the SM-DP+ address and activation code so you have the manual fallback offline.
- Check Carrier Lock in advance: Settings → General → About → Carrier Lock should read "No SIM restrictions".
- Expect "no service" after installing and before landing — that is normal, and not a failed install.
Frequently asked questions
Can I scan the eSIM QR code from the same phone I am installing on?
No. The camera cannot photograph its own screen. Display the code on a laptop, tablet, or second phone — or skip scanning entirely and enter the SM-DP+ address and activation code manually.
What is an SM-DP+ address?
It is the server address your phone downloads the eSIM profile from. Together with the activation code it is exactly what the QR image encodes, which is why manual entry produces an identical result to scanning.
Why does it say "Unable to Add Cellular Plan"?
Almost always no working internet at the moment of install, since the phone has to download the profile. Connect to stable Wi-Fi and retry. If it persists on good Wi-Fi, the code may already have been used.
Can I install the eSIM without internet?
No. The profile is downloaded from the provider at install time, so you need Wi-Fi or an existing data connection. This is why installing before you travel is worth doing.
I scanned the code twice by accident. Is the plan gone?
Not necessarily. A second scan usually just fails harmlessly because the code is spent. The plan is only at risk if you deleted an installed profile. Contact your provider before buying a replacement.
Sources & further reading
Daniel Reyes
eSIM & Mobile Networks Writer
Daniel is a telecoms writer who has covered mobile networks and eSIM technology since 2019. He breaks down carrier coverage, device compatibility, and activation step by step.