A code won't scan. Search by name

Brightness first. A dim screen is the usual reason a code will not read, and a cracked screen is the next.

If it still will not, the scanner's door mode has a Can't scan? Search by name button. It opens the attendee list, every ticket-holder and guest pass for the night, with who is already in. Type part of the name to narrow it, then press Check in on the person's row. A confirmation slides up; press Done and you are back in the list for the next one.

A check-in by name is the same as a scan: the ticket is marked used, the counts update, and the code will not scan again.