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Today the backtest button stopped working for me. No error message or anything. I just click it, and it does nothing. The terminal tells me the project is building, but nothing happens. I have tried to run multiple algorithms, including ones that I have successfully backtested before. Is the python compiler down or something? Or is it an issue specific to my account?
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Mia Alissi
Hi Zachary, sorry you're having this frustration! Here are some steps to troubleshoot when the backtest button doesn't work, but the terminal says it's building with no error:
Check QuantConnect Status: Sometimes the issue is on QuantConnect's side, especially if it suddenly affects multiple working projects or there's no error message. Visit the QuantConnect status page or forums to see if others report a Python compiler or cloud outage.
Browser Refresh & Cache: Refresh your browser and clear your cache. Occasionally, stale sessions or corrupted cache can cause UI buttons to malfunction.
Browser Console: Open your browser's Developer Tools (usually F12 or right click → Inspect) and try hitting the backtest button. Look for errors or warnings in the Console tab and note any red text.
Test with New/Sample Project: Create a brand new QuantConnect project or run a basic sample algorithm. If backtesting works there, the problem is likely in your specific project; if not, it's account-wide or platform-wide.
Duplicate or Export Project: Try duplicating your project, or copy-paste the main code into a new project and see if the issue persists. Sometimes project files or metadata may get corrupted.
Log Out and Log In: Fully log out of your QuantConnect account, then back in, to reset your session.
Contact Support with Details: If none of the above works, contact QuantConnect support. Provide your username, project name/ID, timestamp of attempted backtest, and any output from your browser's Console/terminal.
Monitor Forums/Discord: Sometimes platform-wide outages resolve quickly and are announced by staff.
Let me know what you find, and feel free to paste any error messages or details if you need further help!
Sources: Getting Started - QuantConnect.com, Getting Started - QuantConnect.com, Debugging - QuantConnect.com
The material on this website is provided for informational purposes only and does not constitute an offer to sell, a solicitation to buy, or a recommendation or endorsement for any security or strategy, nor does it constitute an offer to provide investment advisory services by QuantConnect. In addition, the material offers no opinion with respect to the suitability of any security or specific investment. QuantConnect makes no guarantees as to the accuracy or completeness of the views expressed in the website. The views are subject to change, and may have become unreliable for various reasons, including changes in market conditions or economic circumstances. All investments involve risk, including loss of principal. You should consult with an investment professional before making any investment decisions.
M Tom
Same here.
Issue persists across multiple devices and browsers.
Lenny joseph james
Same here
AK M
Bump. It's also affecting Live Deploy. I got an error that one of the security certificates was expired. Maybe related?
M Tom
Can confirm, Live Deploy is also affected.
M Tom
Status page shows everything online:Â
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However, users on discord are also experiencing the issue:
RyRidge
Same here, so far, the only thing I found that works is using the Lean CLI to do backtest or Live deploy.Â
Trader Ostburg
M Tom
Looks like there may be a websocket server down
Jared Broad
Hi All,
I'm really sorry there was an outage of streaming packets last night which has been resolved. Because it was streaming only it didn't trigger our real-time alarms. A simple certificate expired and we failed to update it in time. We had it queued up and did the procurement on Friday but just lost track of time.
We'll hook up our real-time alarms to a certificate monitoring system going forward to prevent this happening again.
Best,
Jared
The material on this website is provided for informational purposes only and does not constitute an offer to sell, a solicitation to buy, or a recommendation or endorsement for any security or strategy, nor does it constitute an offer to provide investment advisory services by QuantConnect. In addition, the material offers no opinion with respect to the suitability of any security or specific investment. QuantConnect makes no guarantees as to the accuracy or completeness of the views expressed in the website. The views are subject to change, and may have become unreliable for various reasons, including changes in market conditions or economic circumstances. All investments involve risk, including loss of principal. You should consult with an investment professional before making any investment decisions.
Zachary Allgood
The material on this website is provided for informational purposes only and does not constitute an offer to sell, a solicitation to buy, or a recommendation or endorsement for any security or strategy, nor does it constitute an offer to provide investment advisory services by QuantConnect. In addition, the material offers no opinion with respect to the suitability of any security or specific investment. QuantConnect makes no guarantees as to the accuracy or completeness of the views expressed in the website. The views are subject to change, and may have become unreliable for various reasons, including changes in market conditions or economic circumstances. All investments involve risk, including loss of principal. You should consult with an investment professional before making any investment decisions.
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