Fail to start PHP FastCGI server after creating new domain

I am using Virtualmin with NGINX on Debian 8, and after I did an apt-get upgrade, I cannot create a new server for a domain. The PHP FastCGI server is not being started for the domain.

Creating administration group sample.com
… done

Creating administration user sample.com
… done

Creating aliases for administration user …
… done

Adding administration user to groups …
… done

Creating home directory …
… done

Creating mailbox for administration user …
… done

Creating Nginx virtual host …
… done

Starting PHP FastCGI server …
… Nginx website failed! : virtualmin-nginx::feature_setup failed : virtualmin-nginx::feature_save_web_php_mode failed : No PHP command found! at …/web-lib-funcs.pl line 1465.

Setting up log file rotation …
… no logging directive found in webserver configuration!

Creating MySQL login …
… done

Creating MySQL database sample_com …
… done

Creating SSL certificate and private key …
… done

Adding SSL to Nginx virtual host …
… done

Creating Webmin user …
… done

Applying Nginx configuration …
… done

Re-starting Webmin …
… done

Re-starting Usermin …
… done

Re-loading Webmin …
… done

Saving server details …
… done