Interactive Brokers TWS API message code
Interactive Brokers TWS API message code: 501 (already connected)
The error, as text you can copy
501- Kind
- TWS API message code
- Where you meet it
- In the TWS API, not in the Web API and not in an HTTP status
What does 501 (already connected) mean on the Interactive Brokers API?
Interactive Brokers lists TWS API client error code 501 with the text "Already Connected." (the vendor's wording). This is a client error: it is raised in the TWS API client code and is never sent by TWS. The client application is already connected to TWS.
Risk warning: CFDs and spread bets are complex instruments and come with a high risk of losing money rapidly due to leverage. You can lose money on these products, and each provider publishes its own loss figure under FCA rules. You should consider whether you understand how they work and whether you can afford to take the high risk of losing your money. Automated and API trading can amplify losses through bugs, connectivity failures and runaway orders.
No fix in the source
The vendor's page gives no remedy.
That is all the source says, so this page does not invent a fix. General guidance: the other tWS API message codes recorded for Interactive Brokers, and the error lookup for the exact text of the reply you received.