To fix the issue with Market Data in TWS/IB in a paper account you have to finish these 2 steps:
✅ Step 1. Share market data subscription with paper trading account
✅ Step 2. Activating proper Market Data Subscription (for SPX options, VIX data and etc.)
Step 1. Sharing Live Data with Paper Trading User
A) On IBKR Website, click your name in the top right corner, then the Settings menu item.
B) Under Account Configuration on the left side of the page, select Paper Trading Account
C) Switch the Share real-time market data toggle to Yes and select your paper trading username from the dropdown and click Save.
Step 2. Activating proper Market Data Subscription in IB
Go to IB Client Portal -> Settings -> Market Data Subscriptions
To Trade SPX with IBKR you will need to subscribe to the following market data bundles:
OPRA (US Options Exchanges) (NP,L1)
Cboe One Add-On Bundle (NP,L1)
US Futures and Index Value Bundle plus OTC Markets (NP,L1)
or US Securities Snapshot and Futures Value Bundle (NP,L1) (in some countries)Your subscriptions should look like the screenshot
In different countries subscriptions may look slightly different.