When a check-in fails
Every message a student can get, what causes it, and what to do. The messages below are exactly what appears on their screen.
In class, do not debug — override. Mark the student present by hand and carry on. A room of thirty waiting while you diagnose one phone costs more than a manually marked record. Diagnose afterwards, from this page.
The messages
"QR code is invalid or expired. Please scan the current QR code on the screen."
The code they scanned has rotated away. Usually a screenshot, a photo of the screen taken earlier, or a slow scan.
Fix: have them scan the live code again. If it repeats for everyone, your projected code may be refreshing too slowly to be scanned — try the projection view.
"Student ID not found in this class. Please check your ID and try again."
The ID they typed does not match any student in the group.
Fix: check what they typed — leading zeros and stray spaces are the usual culprits. If it is right, they are not in the group, or their ID is stored wrong. Add them or correct the record.
This one is worth catching early. Import a class list and check that a few students can actually check in before the term depends on it.
"This session has ended"
Check-in is closed — you ended it, or the duration expired.
Fix: override. Sessions cannot reopen. If it keeps happening, your session duration is too short.
"This session has expired"
Same as above: the duration ran out.
Fix: override, and set a longer duration next time.
When the phone sends no location
The session has a geofence and the student's phone gave no position. The message says why, so you can tell which fix applies:
| They see | Cause | Fix |
|---|---|---|
| "Location is blocked for this site. Allow location access in your browser settings, then try again." | They denied the permission prompt, now or earlier | Re-allow location for the site in the browser's settings |
| "Your phone could not find your location. Turn on location services, then try again." | Location services are off for the phone | Turn them on and scan again |
| "Your location took too long to load. Allow location if asked, move near a window if you are indoors, then try again." | No fix in time — weak signal indoors, or a permission prompt left unanswered | Answer the prompt, move near a window, retry |
| "This browser cannot share your location. Open the check-in link in your phone's normal browser and try again." | A browser with no location support — usually one built into another app | Open the link in Safari or Chrome |
| "Location access is required for this session. Please enable location and try again." | Anything else | Enable location and retry |
None of these is recorded as a violation — nobody was measured. On iOS, re-enabling a denied permission lives in Settings and is not a thirty-second fix; override and move on.
"You are outside the allowed area for this session. Your attempt has been recorded."
Their location is outside your radius.
Fix: if they are visibly in the room, your radius is too tight or GPS is poor indoors. Override them, then widen the radius for future sessions. See Choosing a radius.
The attempt, its distance and the phone's reported accuracy appear in the session's Violations tab.
"This device has already been used to check in another student. Your attempt has been recorded."
This browser already checked someone else in during this session.
It is recorded as a Duplicate device violation.
Fix: if it is genuine device sharing — a dead battery, a borrowed phone — override. If not, see How Quorum stops proxy check-ins.
"Your browser could not be identified. Please re-open the check-in link in your normal browser and try again."
Almost always a private or incognito window, or a browser with aggressive privacy settings.
Fix: re-open the link in their normal browser. Worth mentioning to a class in advance — students who browse in private mode by habit hit this every time.
"Too many failed attempts. Please check with your instructor."
Ten university IDs that are not in the group, within five minutes, for this session, from one network address. Quorum cuts guessing off quickly; the lock lifts after a few minutes.
On shared campus Wi-Fi, a whole room can sit behind one address, so a handful of typos from different students can add up. If several students hit this at once, ask them to switch to mobile data.
Fix: override them, and check their IDs against the roster.
"Attendance recorded successfully! (Note: A device similarity was flagged for review.)"
Not a failure — they are checked in. Their phone looks like one that checked in a different student, so the session gets a Similar device entry for you to look at. See How Quorum stops proxy check-ins.
"You have already checked in for this session."
They are already checked in. Nothing is wrong.
"Network error. Please try again."
The phone lost connectivity mid-request.
Fix: try again. In a hall with poor signal expect a handful of these — a reason not to set a two-minute duration.
Nothing happens when they scan
The camera does not open the page at all.
- Some older camera apps do not handle QR codes; a browser-based scanner works.
- A dirty or cracked lens, a dim screen, or a shallow angle from the back row.
- Switch to the projection view for a bigger code.
The whole class is failing
Stop and look at the pattern rather than the individuals.
| Everyone gets | Suspect |
|---|---|
| Invalid or expired | Projected code not refreshing — check your screen is live |
| ID not found | Wrong group, or IDs imported into the wrong field |
| Outside allowed area | Radius too tight, or session started from your office |
| Nothing at all | Code too small or too far away |
Next
- Fix an attendance record
- What your students do — forward it before the first session