An eSIM that worked yesterday and fails today has almost always hit one of four things: the data allowance ran out, the validity window closed, you moved outside the plan’s coverage, or a software update reset a per line setting. Sudden failures are rarely faults, which is good news, because all four of those have fast answers.
This page gives you a way to identify which one you are looking at in about two minutes, then the fix for each. It covers the same ground whether the phone shows no service, connected with no internet, or simply nothing loading.
In this guide:
- Identify the cause in two minutes
- Cause one: the plan ended
- Cause two: you moved out of coverage
- Cause three: a software update reset a setting
- Cause four: the network handed you over badly
- The one cause people always suspect and it never is
- If none of those apply
- If the plan ended, replacing it takes minutes
Identify the cause in two minutes
Three questions, in this order, resolve the large majority of sudden failures.
- Does the plan still have data and days left? Check the provider’s account page or your order email, not just the phone’s counter. If either has run out, stop here: you need a top up or a new plan, not troubleshooting.
- Are you in a country the plan covers? Check the plan’s country list by name. Borders, ferries, overnight trains and long layovers all move people out of coverage without any decision on their part.
- Did the phone update or restart recently? If so, check that the travel line is still enabled, still selected as the data line, and still has data roaming switched on.
If all three come back clean, the cause is almost certainly a network handover problem, which the section below covers and which usually clears with one aeroplane mode cycle.
| Symptom | Most likely cause | Fix |
|---|---|---|
| Worked all trip, stopped on a specific date | Validity expired | New plan or top up |
| Slowed first, then stopped | Allowance exhausted | Top up |
| Stopped after crossing a border or landing | Outside plan coverage | Check country list |
| Stopped after a system update | A per line setting reset | Re enable roaming and data line |
| Stopped mid day in one spot, signal bars still showing | Failed network handover | Aeroplane mode cycle, manual network selection |
Cause one: the plan ended
Prepaid travel plans end in two different ways, and they feel different.
Ending on validity is abrupt. The plan stops on a date regardless of how much data is left, which is why a plan bought with a seven day window stops working on day eight even with gigabytes unused. Our guide to validity periods covers how the window is counted, including whether it starts at purchase or first connection.
Ending on data is often gradual. Some plans slow before they stop, which is throttling, and others cut off cleanly. If pages started loading slowly a day before failing entirely, this is what happened.
Either way the fix is the same: buy more. A top up is usually the faster route if the provider offers one for your plan, and a fresh plan is the answer if they do not. Both are covered in what to do when you run out of data abroad.
Cause two: you moved out of coverage
A plan’s coverage is a list of countries, not a region on a map, and phones do not warn you when you leave it. Your handset will often keep showing full signal bars from a network it is not permitted to use, which is why this cause is so consistently misread as a fault.
Four situations where it catches people:
- A land border crossing, including day trips that were not in the original itinerary.
- A transit stop in a third country on the way home.
- Ferries and coastal areas, where the phone can latch onto a network across the water.
- Non EU countries inside geographic Europe, particularly the UK, Switzerland and Turkey, as covered in does a Europe eSIM work there.
The fix is to check the plan’s country list against where you actually are. If you are outside it, either you return to covered territory or you buy a plan for where you now stand. Plans by country are on the destinations index.
Cause three: a software update reset a setting
Major iOS and Android releases occasionally reset per line preferences. The profile survives and the plan is untouched, but the phone starts routing data differently than it did before.
Three settings to re check after any update:
- The travel line is still enabled.
- The travel line is still selected as the mobile data line, not merely switched on.
- Data roaming is on for that line. Travel eSIMs connect as roaming partners, so with it off you register and then pass no traffic.
Samsung users should also re check that mobile data did not move back to the home line, which is covered with the exact menu path in eSIM not working on Samsung and Android.
Cause four: the network handed you over badly
Mobile networks hand devices between cells and sometimes between partner operators. Occasionally a handover leaves a device registered but with no working data session, which produces the classic connected with no internet state while the signal bars look perfect.
The fix is to force a fresh registration:
- Toggle aeroplane mode on, wait thirty seconds, then off.
- If that fails, restart the phone.
- If it still fails, turn off automatic network selection and choose an operator manually, as described in network selection when there is no signal.
This is also the fix for a line that works in one town and not the next, where a second operator is available but the phone keeps trying the first.
The one cause people always suspect and it never is
Hardware. An eSIM lives on a chip soldered into the phone, with no connector to work loose, no card to slip in its tray and no contacts to oxidise. That absence of moving parts is one of the genuine advantages of the technology, covered in eSIM versus physical SIM, and it means a working eSIM does not fail mechanically overnight.
Two things follow. A factory reset fixes none of the four causes above and costs you an afternoon, so it is never the right next step. And the fact that your other line still works is not evidence that the travel plan is broken: your home line is a different subscription on a different network with different roaming permissions, so the two failing independently is normal rather than diagnostic.
If the phone genuinely will not connect on any line, that is a different problem and why your phone is slow abroad covers the network side of it.
If none of those apply
Work through the ordered checks in the complete eSIM troubleshooting guide, which adds APN settings and the checks this page skips, and see eSIM installed but no data if the line is registered and only data is missing.
Then contact your provider with three specifics: what changed immediately before it stopped, the country and city you are in, and your order reference. Those three let support check the subscription record directly. Do not delete the profile first, because most travel profiles use single use codes and cannot be reinstalled.
If the plan ended, replacing it takes minutes
Two of the four causes on this page, an expired window and an exhausted allowance, are not faults at all. They mean the plan finished, and the fix is another plan.
Viasimo sells prepaid travel eSIMs for more than 190 destinations with the size, validity and covered countries shown before you pay, so you can buy exactly the days you have left rather than starting a full trip plan again. The QR code arrives by email in minutes, installs from your phone’s own settings with no app, and the purchase is one off with nothing renewing afterwards.
Buy for where you actually are: USA, Europe, Japan, Thailand, or the full destinations index.
Ready to compare plans directly? The eSIM plan picker takes a destination and a number of days and shows what is available for them.
