Why can't the bus ticket be issued?

The bus ticket can't be issued, which may be due to system failure or the ticket is sold out.

1, system failure may lead to ticket failure. For example, network connection problems, server failures or software errors may affect the normal operation of the ticketing system, resulting in the failure to issue tickets successfully.

2. If the tickets are sold out, the system will display that there are no tickets or sold out when purchasing tickets, and the tickets cannot be issued successfully.