Most problems in a room come from the network address, the browser’s sound policy or a choice made in the lobby. Find the message or the symptom below; the sections after the tables cover the longer cases. When the cause is an instance setting, ask whoever runs your instance.
| Symptom or message |
Cause |
Fix |
| “No open room with this PIN. Check the big screen.” |
A typo in the PIN, or the room is closed. |
Check the 6 digits on the big screen. A closed room’s PIN does not work again: open a new room. |
| “This room is closed to newcomers; a participant coming back still gets in.” |
You chose Close the room to new participants. |
In the console, switch Closed to newcomers back to Open to newcomers. |
| “This nickname is already taken in this room.” |
Another player has it. |
Pick another nickname. |
| “The nickname must be between 2 and 20 characters.” |
Too short or too long. |
2 to 20 characters. |
| “Too many wrong PINs from this address. Try again in a minute.” |
Too many wrong PINs from one network address within a minute. Phones on the same Wi-Fi often share one address. |
Wait a minute, then type the PIN carefully, or share the QR code or the direct link instead. |
| Phones cannot open the address at all |
The invitation address is localhost, or on a network the phones are not on, or a firewall blocks the port. |
See Phones cannot reach the room. |
| Phones warn that the address is not secure |
The instance is served over HTTPS and the invitation address is a local http:// one. |
Use the public address when there is one. |
| Players are asked to sign in |
OIDC mode with Accounts required. |
Players sign in, or choose Open access at the next launch if the instance allows it. |
| “You have been removed from the room.” |
The player was banned. |
The ban ends after the time chosen (5 minutes by default). |
| Symptom or message |
Cause |
Fix |
| No sound on the big screen |
The browser allows sound only after a click in the projection window. |
Click in the projection window and choose Turn sound on. See No sound. |
| “Video started without sound (blocked by the browser)” |
The same browser rule. |
Click once in the projection window. |
| The console is silent |
On purpose: the projection plays the sound. |
Use Hear “{name}” (here only) in Room sound to check a sound. |
| “Loading the question’s media” lasts |
Some devices are still loading the media. |
Wait (10 seconds at most by default) or choose Start anyway. |
| “Your answer arrived too late: it is not counted.” |
The answer reached the server after the question closed (end of time plus 0.3 seconds). |
Nothing to fix: late answers score 0. |
| “Too early: the answers were not open yet. Answer again.” |
The player answered during the reading time. |
Answer again once the answers open. |
| “Quiz paused — host disconnected.” |
Your console lost the connection. |
Reopen the room with Resume in Open rooms within 2 minutes. |
| Phones show no video |
Phones in the room play a question’s video only when its sound reaches Every device: otherwise the big screen does. |
Players who cannot see the big screen choose Remote when they join. |
| Symptom or message |
Cause |
Fix |
| “The quiz must be “ready” to be played (RG-02).” |
The quiz is a draft. |
Choose Publish (ready). |
| “{n} steps are unfinished: complete them to publish the quiz.” |
Some questions or slides are incomplete. |
Open each one from the checklist and finish it. |
| “This quiz is being played in a room: close the room first.” |
You tried to delete a quiz that a room is playing. |
Close the room, then delete. |
| “Someone saved at the same time. Try again.” |
Two saves arrived together. |
Save again. |
| “The host seat is held by someone else: you can only join rooms as a participant.” |
Local mode: another person holds the seat. |
Wait for the seat to expire, ask the holder to release it, or ask an administrator to free it. |
| “This name does not hold the seat: only its holder signs back in.” |
The name typed is not the seat holder’s. |
Type the exact name used to take the seat. |
| “Host role required.” |
OIDC mode: your account has no host role. |
Ask whoever runs your instance for the Host role. |
| Message |
Cause |
Fix |
| “Not a QuizDock bundle (quiz.json + media/, zipped).” |
The file cannot be read, or its structure is not QuizDock’s: a .zip not made by QuizDock’s Export, a quiz.json that is not JSON or misses a part. |
Export the quiz again from QuizDock, or check the quiz.json against the format. |
| “Use the original Kahoot spreadsheet template (.xlsx), with one sheet.” |
The spreadsheet is not Kahoot’s template. |
Copy the questions into the official template, or use the chatbot conversion. |
| “No valid questions found. Check row 9 and the Kahoot template.” |
No row could be converted. |
Check the rows from row 9 down. |
| “File too large to import (at most 50 MB).” |
The file is over the instance’s import limit. |
Lighten the media, or ask whoever runs your instance. |
See Import a quiz.
- Look at the invitation address in the console.
localhost or 127.0.0.1 only works on the computer itself: choose another address under Invitation address.
- On a local instance, pick the computer’s address on the network the players use (an IP such as
192.168.x.x, with the port of the page). When no local address was detected, Why this address? shows where to find it on Mac, Windows and Linux.
- Check that the phones are on the same Wi-Fi as the computer. Guest Wi-Fi networks often keep devices apart.
- Check that the computer’s firewall lets the port through.
- Test with your own phone: scan the QR code before players arrive.
The invitation address cannot change once the quiz has started. If no local address is listed, type it under Other address…; whoever runs your instance can make it appear. See Networking.
- Click once anywhere in the projection window, and choose Turn sound on if it shows. The click must be in that window, not in the console.
- Open Room sound and check that Projection sound is on (the console shows Room muted when it is off) and that the Media level is up.
- Check the question’s Who hears this sound, and the lobby’s Who hears the sound in this quiz.
- Check the computer’s volume and its sound output (HDMI, speakers).
- Use Chrome or Edge for the projection.
| Message |
Fix |
| “QuickTime files (.mov) are not accepted.” |
A .mov reached the server without being converted. Upload it from the editor in Chrome or Edge, which converts it to MP4, or export it as MP4 (H.264) with HandBrake. |
| “Unsupported video codec (…).” |
Often a video shot on an iPhone. Convert it to MP4 H.264 with HandBrake, or set the camera to “Most Compatible”. |
| “This browser cannot convert this video to MP4 H.264.” |
Use Chrome or Edge, or convert it first with HandBrake. |
| “This browser cannot convert this sound to AAC.” |
Try Chrome or Edge, or convert it first with Audacity. |
| “File too large (at most 50 MB for this kind of media).” |
Shorten or compress the file. The limit is the instance’s. |
| “Too long to fit the 50 MB limit for this kind of media, even compressed.” |
Shorten the video first. |
| “Media uploads are disabled on the demo instance.” |
Uploads are off on the live demo. |
SVG pictures are not accepted: export them as PNG. See Media.
