Whiteboard.fi has a session-level limit for students
Your session's student limit is indicated in the upper left corner:
Limits
| User type: | Limit: |
| Free user (no account) | 10 students per session |
| Registered user (free account) | 20 students per session |
| Lite Plan ✴️ | 30 students per session |
| Pro Plan ✴️ | 40 students per session |
| Premium Plan ✴️ | 100 students per session |