Error -50 when attempting to store a SymmetricKey in Keychain

Hi all,
I've been working on implementing CryptoKit in my app, and I seem to have run into a wall where I can't get the generated SymmetricKey to be stored in the keychain. Here is the code I've written:

Code Block swift
    static func makeAndStoreKey(name: String) throws -> SymmetricKey? {
        let nameData = name.data(using: .utf8)
        let symmetricKey = SymmetricKey(size: .bits256)
        let query = [kSecClass: kSecClassGenericPassword,
                     kSecAttrApplicationTag: nameData!,
                     kSecValueRef: symmetricKey.rawRepresentation] as [String: Any]
        let status = SecItemAdd(query as CFDictionary, nil)
        guard status == errSecSuccess else {
            throw KeyStoreError("Unable to store item: \(status.message)")
        }
        return symmetricKey
    }
    static func loadKey(name: String)  throws -> SymmetricKey? {
        let nameData = name.data(using: .utf8)
        let query = [kSecClass: kSecClassGenericPassword,
                     kSecAttrApplicationTag: nameData!,
                     kSecReturnRef: true] as [String: Any]
        var item: CFTypeRef?
        switch SecItemCopyMatching(query as CFDictionary, &item) {
        case errSecSuccess:
            guard let data = item as? Data else { return nil }
            return SymmetricKey(data: data)  
        case errSecItemNotFound: return nil
        case let status: throw KeyStoreError("Keychain read failed: \(status.message)")
        }
    }

I was also attempting to add the following attributes to the keychain query (but commented them out because I was attempting to troubleshoot this issue)

Code Block swift
                     kSecAttrIsPermanent: true,
                     kSecAttrCanEncrypt: true,
                     kSecAttrCanDecrypt: true,
                     kSecAttrAccessible: kSecAttrAccessibleWhenUnlocked,
                     kSecUseDataProtectionKeychain: true,
                     kSecAttrIsInvisible: true,

I've tried storing the key as both a a kSecClassGenericPassword and a kSecClassKey, and it returns the same -50 ("One or more parameters passed to a function were not valid.") error. I've tried storing the key as both Data and the SymmetricKey iteself, and I have tried storing the ApplicationTag as both a String and as Data. Neither of these resolve the issue. I'm hoping someone has some ideas on what I'm missing here.

I've been following the instructions listed here: https://developer.apple.com/documentation/cryptokit/storing_cryptokit_keys_in_the_keychain

Here is my code to convert to a rawRepresentation (the code supplied in the CryptoKit Keys in the Keychain article didn't compile unfortunately).

Code Block swift
import Foundation
import CryptoKit
extension SymmetricKey: GenericPasswordConvertible {
    public var description: String {
        return ""
    }
    init<D>(rawRepresentation data: D) throws where D: ContiguousBytes {
        self.init(data: data)
    }
    var rawRepresentation: Data {
        var intArr = [UInt8]()
        self.withUnsafeBytes { ptr in
            intArr.append(contentsOf: ptr)
        }
        return Data(intArr)
    }
}

Thanks in advance for the help.