market data WebSocket subscription fails with error code -300 (type: sub).

Automate, API & MCP
1

Hello Team,

My FYERS API v3 REST APIs are working fine, but

market data WebSocket subscription fails with error code -300 (type: sub).

Please enable Market Data WebSocket / Streaming permission

for my API app UEH9JSNIFQ-100.

Thanks.

2

Hey @110092242570660931869,

There is no separate permission required for socket usage. 300 error is related to an invalid symbol. Please ensure that subscribed symbols are valid.

3

“NSE:NIFTY50-INDEX”,

"NSE:BANKNIFTY-INDEX"
4

These are valid symbols. Please DM your client ID, we will connect and debug this further.