Coredata issue : Unresolved error: Error Domain=NSSQLiteErrorDomain Code=778 "(null)"

I am facing issues When i try to call loggedInCustomer method

Logic:

+ (Customer *)loggedInCustomer {
    if (!_loggedInCustomer) {
        _loggedInCustomer = [Customer loggedInCustomerInContext:CoreDataManager.shared.mainManagedObjectContext];
    }
    return _loggedInCustomer;
}

 @objc private(set) lazy var mainManagedObjectContext: NSManagedObjectContext = {
        let managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
        managedObjectContext.persistentStoreCoordinator = self.persistentStoreCoordinator
        managedObjectContext.mergePolicy = NSOverwriteMergePolicy

        return managedObjectContext
    }()

Issue:

Unresolved error: Error Domain=NSSQLiteErrorDomain Code=778 "(null)" UserInfo={NSFilePath=/var/mobile/Containers/Data/Application/E00DDCF6-853D-4E17-BDF6-C6C86BC9E707/Documents/xyz.sqlite, NSSQLiteErrorDomain=778}