Cannot Modify Headers Error

When responding to a request, certain data needs to go first, like cookies. The message indicates that JFBConnect is trying to set a cookie or otherwise sending some output to the browser. Then, later, another extension is also trying to output some data that needed to go first and it's complaining.

Normally, Joomla should take care of this ordering, so you shouldn't see that error. It's something we can gladly help you investigate further though.

Can you let us know what version of JFBConnect are you using? The latest is v8.4.6 for Joomla 3.x or the 9.0Beta which is compatible with both Joomla 3 and Joomla 4.

Thanks,
Alex

If it was working fine until recently, that would likely point to something else being the cause. Have you installed other extensions or changed their configuration recently?

I do not believe upgrading JFBConnect would fix this as it's not an issue we're aware of. However, we always recommend being on the latest version for the highest compatibility.

With that said, here's the best recommendations I can provide:
* Update Joomla. 3.9.12 is very old and there have been multiple security updates as well as bug-fixes since that release.
* If you have Error Reporting in Joomla enabled, disable it. Since the message you're seeing is a warning, disabling error reporting will hide that message. It's not a fix, but it will probably make the problem go away.

I hope that helps,
Alex