Why can’t I check in online? The possible reasons explained (2024)

Your bags are packed, your passport’s at the ready, and you’re all set for your next adventure — but when you try to check in for your flight online, you get an error message. “We cannot check you in at this time,” it says, “please check in at the airport.” There’s no obvious reason for it, such as being too late to check in online. It wouldn’t be such a problem, except now you can’t select your own seat and you have to put up with the long queues at the airport. It’s frustrating, yes, but there are myriad reasons why it can happen — and some have an easy fix.

Main photo: it’s not always possible to check in using a smartphone or tablet (Getty Images)

You’re trying to check in with the wrong airline

Flights are often operated on a codeshare basis, which means the airline you booked with might not necessarily be the one you’re flying with.

So while you might get an email asking you to check in, you won’t be able to do it on the website of the airline you booked with — instead, you’ll need to check in via the website of the airline you’re actually flying with.

Look through your emails; there’s usually a second booking reference somewhere that mentions the codeshare partner and this is the one you need to use on the codeshare partner’s website to check in.

There’s a technical problem

Glitches on websites and apps happen all the time, whether it’s through human error, a system update or simply incompatibility with your device.

If you’re denied online check-in, it might be worth retrying a few hours later or on a different device. Sometimes, you might be able to check in online using a laptop but not your phone or tablet.

The flight has been overbooked

Airlines often oversell flights so that when passengers fail to turn up or switch their booking to another date, they have spares to fill up those empty seats.

The downside, of course is, that when everyone does turn up for their flight, there aren’t enough seats — so they’ll have to bump some passengers onto a later flight.

So if you can’t check in online, it may be a sign that you’re being held back for a later flight. In some cases, a space can become available at the last minute, which is why you’re then able to check in at the airport as if nothing’s happened.

There’s an operational reason

Apart from an overbooked flight, there are lots of operational reasons why there are no longer enough seats available. This might include a change of aircraft, meaning that there are now too many passengers to fly, or that some pre-allocated seats are no longer available. You may also be bumped from the flight to allow crew on standby to travel.

You haven’t filled in all the required information

For long-haul destinations, especially flights to the US, you often need to fill in additional passenger information before you travel.

In the case of the US, for example, this includes whether you’re travelling on an Esta or a visa, and where you’re staying. Some destinations will also require you to submit your passport details before you travel.

It’s always worth checking whether you need to submit any additional documents or information after your booking as it may be too late by the time you check in.

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An in-person document check is required

Depending on your destination, airlines may need to carry out additional checks, such as whether you have the right visas or if your passport is still valid, which can only be done in person at the airport. This applies to all passengers.

In some cases, you may be singled out for additional checks because you’ve been flagged as suspicious.

Reasons might include: if you have more than one passport, if you’re a certain nationality, if your flight was booked at the very last minute, if your flight was booked by someone else, or if you have the same name as a person of interest.

And if you’re travelling alone with children, you might also be flagged if you have a different surname to them. You’ll need to carry additional documents, such as a birth certificate and letter of consent from the other parent, to satisfy border concerns around child trafficking.

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