"txid": "551ba4bde3460bca6a6cae7da57ffd8b3f1baf18ad7a2e6d50f8d4f5b0a94e14",
"vout": 1,
"scriptSig": {
"asm": "0014620cfaeb631c99d45490cc6560a7258835c260f8",
"hex": "160014620cfaeb631c99d45490cc6560a7258835c260f8"
},
"txinwitness": [
"3045022100a1e4403c6327fb787ef498cfaf6c54f8372f2792c06a7156cad6cf15c729de2802201eb1b48e2443b04688091897caf0fc9afbfc002227c05441a5f1723be9a532e401",
"02533dc7b0e2d8f359fb235fd52bcda6135cfb0e39c6d9d93a10704457ff30e6ff"
],
"sequence": 4294967295
}
This is your problem, the input you are spending is a segwit input. You will need to figure out how to prevent your fork from creating segwit outputs that can be spent as inputs.