Transaction not yet indexed

521ExkKBdMg4Bpb6kpcxqPebkLS8NoJWsarQ2SV3FywspmEBhZ29f37wLqgf6QfDYzQdvqPQ93weuvTXz6t16Sqw

The transaction signature is valid but not yet indexed by this RPC node, or the transaction failed before inclusion.