C API error : sqlite error 26 files is encrypted or not a database

We are using sqlite3_prepare_v2 and sqlite3_step C APIs to execute query on sqlite DB.

We are in a situation where we have sqlite db and when we try to execute any query on that DB we get sqlite error 26 file is encrypted or not a database.

Even when we try to run any query on DB from sqlite3 command line, we get the same error.

Can anybody please let me know how to recover this DB?

Thanks