Every webhosting user has a certain number of PHP processes available. When the maximum number of PHP processes for your user has been reached and all of them are occupied, there are no more free processes available. This can lead to longer load times because requests have to wait until a process becomes free. If many requests have to wait, the Error 503 - Service Unavailable appears when calling the website.
In this case, the following error message is displayed in the error log:
[Mon Jul 22 09:22:58 2019] [error] [client 1.2.3.4] mod_hcgi: pm error: user limits reached!
The error log can be accessed via the Control Panel under the "Websites" item, if you click on "Logs" at the corresponding website and then switch to the "Errorlogs" tab. The logs show exactly what is being called. This can help you and your webmaster find the error in your application.
If you have several websites on the same server, the cause does not necessarily have to be at the page with the error messages. It is also possible that one of your other pages is claiming all the processes. If you have configured several web pages with different PHP versions and encounter this error message, we recommend to switch all web pages to a common PHP version.
You have the possibility to terminate all PHP processes via shell with the following command:
killall -9 php-cgiHow to connect to the server via SSH is explained in the article "How do I set up and use SSH?".
Our support will be glad to help if you can not terminate the processes yourself and will help you analyze the problem.
For support requests please use this form instead.