eSIM Not Working? The Complete Troubleshooting Guide (2026)

Most eSIM problems come from one wrong setting on the phone, not from a problem with the eSIM itself. In this guide you'll find the common issues, grouped by stage: before installation, during installation and after installation, abroad. For each one we've included the cause and the exact fix for iPhone and Android.

An important tip first: install the eSIM at home before your flight, connected to stable Wi-Fi. Activation itself (connecting to a network) happens only once you land at your destination.

Part 1: Problems before installation

1. The device doesn't support eSIM

The sign: there's no "Add eSIM" option in the menu, or installation fails immediately.

How to check support:

• Any phone: dial *#06#. If an EID number appears, the phone supports eSIM.
• iPhone: Settings > General > About. Scroll down and look for an EID or Digital SIM line.
• Android: Settings > About phone > SIM status, and look for EID.

Note: some models are sold in different versions in different countries. The same model can support eSIM in one version and not in another, so checking for an EID is the safest way.

2. The device is locked to a carrier

The sign: a message like "Unable to add cellular plan" or "SIM not supported".

The cause: phones bought through a mobile carrier (especially in the US) may be locked to that one carrier.

The fix:

• iPhone: Settings > General > About > Carrier Lock. If it says "No SIM restrictions", the phone is unlocked.
• Android: try inserting a SIM from another carrier. If you get no signal, the phone is locked.
• Contact the company you bought the phone from and ask them to unlock it. This can take time, so do it well in advance.

3. The operating system is out of date

The sign: installation hangs or fails for no clear reason.

The fix: update your operating system to the latest version (iPhone: Settings > General > Software Update). Older versions can cause eSIM installation problems.

Part 2: Problems during installation

4. The QR code won't scan

Common causes:

• You tried to scan the code with the same phone that's displaying it.
• The screen brightness is low or the code is too small.
• The camera isn't focused, or there's glare.

The fix:

• Show the code on another screen (a computer or a second phone) and enlarge it.
• Turn up the brightness on the screen showing the code.
• If you don't have another screen, use manual installation (section 5).

5. How to install an eSIM without scanning the QR code (manual installation)

Your installation email contains two details: the SM-DP+ address and the activation code.

On iPhone: Settings > Cellular > Add eSIM > Use QR Code > Enter Details Manually. Paste both details exactly as they appear.

On Android: on the QR scanning screen, look for an option like "Enter code" or "Need help?" and enter the details.

Tip: copy and paste rather than typing, to avoid mistakes with similar characters like 0 and O.

6. "This code is no longer valid" or "Unable to add cellular plan"

The cause: in most cases, the QR code has already been scanned. Each eSIM code can be installed only once, even if the previous installation didn't complete.

The fix:

• Check whether the eSIM already appears in your phone's list of lines (iPhone: Settings > Cellular).
• If it's there, there's no need to install it again.
• If it isn't, contact FlySim support with your order number.

7. No internet connection during installation

The sign: installation gets stuck on "Downloading" or fails with a generic error.

The cause: installing an eSIM needs a stable internet connection to download the profile.

The fix: connect to a stable Wi-Fi network and try again. Avoid public Wi-Fi with a login page (like in hotels or airports), which can block the download.

8. Installation is stuck on "Activating"

The fix, in order:

1. Wait 5 to 10 minutes. Sometimes it simply takes a while.
2. Turn airplane mode on and off.
3. Restart your phone.
4. If the eSIM appears in the list after restarting, the installation succeeded.

Important: don't delete the eSIM to "start over". Deleting it can disable it permanently.

9. "Unable to complete cellular plan change"

The cause: a temporary communication problem between the phone and the installation server.

The fix: restart your phone, connect to a different Wi-Fi network if you can, and try again after a few minutes. If it keeps happening, contact support.

Part 3: Problems after installation (at your destination)

10. No signal at all ("No Service")

This is the most common problem, and the fix is almost always simple. Check in this order:

a. Is the eSIM turned on?

• iPhone: Settings > Cellular > select the eSIM > make sure "Turn On This Line" is enabled.
• Android: Settings > Connections (or Network & internet) > SIM manager > make sure the eSIM is turned on.

b. Is Data Roaming on? This is the number one cause of problems. A travel eSIM works by roaming, so roaming must be turned on for the eSIM line.

• iPhone: Settings > Cellular > select the eSIM > turn on Data Roaming.
• Android: Settings > Network & internet > SIMs > select the eSIM > turn on Roaming.

c. Are you in a destination your plan covers? Make sure the country you're in is included in the plan you bought.

d. Network selection

• iPhone: Settings > Cellular > the eSIM > Network Selection > turn on Automatic.
• If Automatic doesn't work, turn it off, wait for the list of networks to load, and choose a network manually.

e. Reset Turn airplane mode on and off, and if that doesn't help, restart your phone.

11. Signal but no internet

The sign: you see bars and a network icon (4G/5G), but browsers and apps won't load.

Check in this order:

a. Is the eSIM set as the line for cellular data?

• iPhone: Settings > Cellular > Cellular Data > choose the eSIM.
• Android: SIM manager > Mobile data > choose the eSIM.

b. Is Data Roaming on for the eSIM? (see section 10)

c. APN settings Some eSIMs need a manual APN setting. If your installation email shows an APN value:

• iPhone: Settings > Cellular > the eSIM > Cellular Data Network > enter the APN in the "Cellular Data" field.
• Android: SIM manager > the eSIM > Access Point Names (APN) > add a new APN.

d. Is a VPN on? Turn off any VPN app and check again. A VPN can block the connection while roaming.

e. Has your plan run out? (see section 13)

12. Slow internet

The fix:

• Make sure your network setting allows 4G or 5G (iPhone: Settings > Cellular > the eSIM > Voice & Data).
• Turn off Low Data Mode if it's on.
• Try choosing a different network manually (see section 10d).
• Turn off your VPN.
• Remember that speed also depends on coverage in the area you're in.

13. The plan has run out or won't start

The sign: the internet stopped working after a period of normal use.

The fix: check your data balance with your eSIM number. If the plan is used up or has expired, you can buy a new one.

14. Your phone is using your home SIM and charging you roaming

This is an expensive problem, so it's worth setting up correctly in advance.

The cause: your home line is set for data, or automatic switching between lines is turned on.

The fix:

• Turn off Data Roaming on your home line (Settings > Cellular > your main line > turn off Data Roaming).
• iPhone: Settings > Cellular > Cellular Data > turn off "Allow Cellular Data Switching".
• Android: turn off options like "Auto data switch" in SIM manager.

15. Not receiving calls and texts on your regular number

The cause: your home line has been turned off completely.

The fix: keep your home line turned on for calls and texts, and only turn off data roaming on it. That way you still receive messages (including verification codes from your bank) without paying for data. Note that receiving calls abroad may cost money with your home carrier, so check with them before you travel.

16. Hotspot doesn't work

The fix:

• Make sure the internet works on the phone itself.
• Restart the hotspot.
• Check in your plan details whether internet sharing is supported.

Part 4: Special cases

17. I deleted the eSIM by mistake

Good to know: in most cases, a deleted eSIM can't be reinstalled with the same QR code.

What to do: contact FlySim support with your order number and describe what happened.

To avoid it: never delete an eSIM as a way of fixing a problem. Turning the line off and on, or restarting the phone, is completely safe.

18. I switched phones after installing

An eSIM is installed on a specific device. If you've changed phones, contact support before deleting the eSIM from the old device.

19. I lost the email with the QR code

Check your spam and promotions folders. If you can't find it, contact support with the email address you used for the order.

Quick checklist: 60 seconds to fix most problems

1. The eSIM is turned on in your list of lines.
2. Data Roaming is on for the eSIM line.
3. The eSIM is set as the line for cellular data.
4. Data Roaming is off on your home line.
5. Airplane mode has been turned on and off.
6. The phone has been restarted.
7. VPN is off.

If you've done all of these and the problem persists, contact FlySim support and we'll help you.

eSIM troubleshooting FAQ

Why isn't my eSIM working abroad?

In most cases, Data Roaming isn't turned on for the eSIM line, or the eSIM isn't selected as the line for cellular data. Check those two settings first.

Can I install the eSIM before my flight?

Yes, and we recommend it. Install it at home on stable Wi-Fi, and turn on the line and Data Roaming when you land.

Can I scan the QR code twice?

No. Each code can be installed only once. If installation failed, check whether the eSIM already appears on your phone before trying again.

Will an eSIM affect my regular SIM?

No. Both lines can work side by side, and the eSIM is used only for data abroad.

What should I do if I deleted the eSIM?

Don't try to install it again from the same code. Contact FlySim support with your order number.

How long does it take to install an eSIM?

Usually just a few minutes, as long as you have a stable internet connection.

Planning a trip? Choose a FlySim eSIM plan, install it in advance using this guide, and land connected.