Sometimes it may happen that the database files get corrupted due to different reasons.
Your debug.log will provide you a message like the below:
"2022-06-16T05:02:54Z [0%]...*** Found EvoDB inconsistency, you must reindex to continue
2022-06-16T05:02:54Z Error: Error: A fatal internal error occurred, see debug.log for details
2022-06-16T05:02:54Z ERROR: VerifyDB(): *** irrecoverable inconsistency in block data at 1687205, hash=000000000000001b55bf6473640747c047b764793d2b0cd249608854f8b227fc"
In order to solve the issue simply start Dash Core wallet with the -reindex command line parameter to initiate a reindex. Alternatively, you can add reindex=1 to the dash.conf file before starting Dash Core but it's very important to remember to remove that line from the file before the next time you restart or it will start the lengthy process of syncing all over again.