Question: why irctc service not available?
Answer: The actual maintaince of IRCTC takes from 11.30 PM to 00.30 AM. During this time you are not allowed to book the tickets or check the PNR status of any train. ... 23:30 to 00:30 is server maintenance in IRCTC, Hence you will not be able to book tickets/check availability/Check PNR status.