upstream sent unexpected FastCGI record: 3 while reading response header from upstream

[Maxim Dounin]

Hello!

On Tue, Mar 14, 2017 at 06:01:45PM -0400, jaigupta wrote:

> I am getting random "upstream sent unexpected FastCGI record: 3 while
> reading response header from upstream" while using Nginx with PHP7. So far I
> was waiting for bug https://bugs.php.net/bug.php?id=67583 to be fixed by PHP
> which they now have but I still get this error.
> 
> Everything works fine for few days and then suddenly I start getting this
> error. How can I debug this in detail? Is there a way I could see or log
> response from PHP (FastCGI) when this error occurs?

Try debug log, see http://nginx.org/en/docs/debugging_log.html for 
details.

-- 
Maxim Dounin
http://nginx.org/