`options_new_trade` returns `INTERNAL_SERVER_ERROR` on mainnet for valid instrument

[johnongit]

Summary

When attempting to create an options trade via the Python SDK, the call to options_new_trade consistently returns:

{ "message": "Internal error", "code": "INTERNAL_SERVER_ERROR" }

Other options endpoints (market, instruments, trades, volatility index, etc.) work fine.

Environment

• SDK: ln-markets Python SDK (latest from PyPI)
• Network: mainnet
• Python: 3.12.9
• OS: Pop OS 22.04

Steps to Reproduce

1. Install the latest ln-markets Python SDK from PyPI.
2. Initialize the REST client on mainnet.
3. Call options_new_trade with the parameters below.

Minimal Code Sample

from lnmarkets import Rest

lnm = Rest(
    key="...",
    secret="...",
    passphrase="...",
    network="mainnet",
)

resp = lnm.options_new_trade(
    side="b",
    quantity=1,
    settlement="cash",
    instrument_name="BTC.2025-12-26.50000.C",
)

print(resp)

Request Payload

{
  "side": "b",
  "quantity": 1,
  "settlement": "cash",
  "instrument_name": "BTC.2025-12-26.50000.C"
}

Expected Behavior

Trade should be created successfully (or a clear validation error should be returned if the payload is invalid).

Actual Behavior

{
  "message": "Internal error",
  "code": "INTERNAL_SERVER_ERROR"
}

What I’ve Tried

• Confirmed instrumentName uses camelCase.
• Verified options_get_market reports active: true.
• Verified the instrument exists via options_get_instruments.
• Tried several instruments from the returned list.
• Other options endpoints (get market, get instruments, my trades, volatility index) all work.

Notes

• Using the smallest possible quantity and cash settlement to be safe.
• This looks like either an API-side issue or an undocumented requirement for options_new_trade.

Workarounds

None found.

Thanks!