AI Research fails at Data Collection with 502 for multiple tickers

Description:
I am using FinRobot Desktop on macOS Apple Silicon.

Basic market data can be loaded successfully, but the full AI Research workflow fails at the Data Collection step for multiple tickers, including AVGO and several other US stocks.

Error message:
"Upstream returned 502"
"Cannot fetch canonical financials"
"all providers failed and no cache is available"

Environment:
- OS: macOS
- Device: Apple Silicon Mac
- FinRobot version: [your version]
- Tested tickers: AVGO, [other tickers]
- Date/time: 2026-08-20, Japan time

Steps to reproduce:
1. Open FinRobot Desktop
2. Enter AVGO
3. Click Analyze
4. Click Run AI Research now
5. The workflow fails at Data Collection after 3 retries

Expected behavior:
The system should collect financial data and generate the AI research report.

Actual behavior:
The Data Collection step fails with a 502 error and the remaining research steps do not start.

Notes:
- FMP, Finnhub and other providers show "Connection OK" in Settings.
- Basic price data works for some tickers.
- API keys have been redacted from the screenshots.