This is the most common issue when installing the Blackfire stack. If this issue occurs, please follow these steps:

1. Make sure the Agent is running

A common situation is where the Blackfire Agent is no longer running. In this situation, the Blackfire Probe will not be able to profile the request. Double-check to make sure that the Blackfire Agent is still running.
On Linux, simply use sudo /etc/init.d/blackfire-agent restart .
Please check our docs for other OS.

2. Make sure the Blackfire probe is properly installed/enabled.

You can use a simple phpinfo() script in a web context and look for Blackfire configuration.

3. Check configuration

Ensure that you properly configured your Blackfire server credentials via blackfire-agent -register . You can display the current configuration with blackfire-agent -d 

4. Restart your web-server or PHP-FPM

And check that there are no error messages.

5. Make sure the page you try to profile is served by PHP

Do you have any proxy, cache or load balancer configured? Make sure they let Blackfire reach the server.
For example profiling a web server directory listing won't work. The same applies for single page web-app as files will probably be served directly by the web server. In this last case, you probably want to profile XHR requests instead.

5. Check versions

Ensure you're using the latest Agent, Probe and Companion. This is quite easy as this page will tell you if they're outdated.

6. Check logs

Collect logs and look for any error messages in the logs.

6. Check if SELinux is enabled

If you are using a flavor of Linux that uses Security-Enhanced Linux (SELinux), see our dedicated information on getting Blackfire to work in SELinux environments.

7. Contact our support

Contact our support via the chat window at the bottom right hand side of the browser window, or via

⚠️  : Don't forget to add both the Probe and the Agent logs. Please understand that our support team will need at least level 4 logs to help you. Read how to collect them here.

⚠️  : If your application is hosted on some of our Hosting Partners, you may not be able to collect agent logs. Please make sure to specify this in your support request.

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