error:06000066:public key routines:OPENSSL_internal:DECODE_ERROR

Hello,

I am trying to use the following code snippet, i am trying to use this for mobile device

```
var publicKey = """
-----BEGIN PUBLIC KEY-----
MMKCASI......xxxxxxxx
-----END PUBLIC KEY-----
""";
var keyData = PemCodec(PemLabel.publicKey).decode(publicKey);

var key = await RsaOaepPublicKey.importSpkiKey(
keyData,
Hash.sha256,
);

```

I am getting the following exception :
`FormatException: error:06000066:public key routines:OPENSSL_internal:DECODE_ERROR`

Any suggestion if i missed anything or anything wrong in the approach?