PHP FPM 5.6 Problem - My Site Gives Error Not Available in FPM 5.6

Hi;

All PHP-FPM versions between 5.3-7.3 are active. However, a site running on 5.6 periodically:

  "Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later. "

Gives a fault.

I think this error was caused by FPM communication errors. FPM repeatedly gives error when closing version 5.6; however, when FPM 5.6 is active, F5 on the site gives "Service Unavialable" error periodically.

https://medicalli.com/ -> Make fast F5 and observe the error.

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