And here is a copy / paste from the MainWP Child site which has WP Staging on it that works, but only if the live site is disabled via an NGINX configuration setting as above.
Configuration du serveur Valeur nécessaire Valeur État
MAINWP CHILD
MainWP Child Version 4.1.2 4.1.2 Pass
MainWP Upload Directory
/var/www/vhosts/domain.tld/httpdocs/wp-content/uploads/mainwp/ Writable Writable Pass
WordPress
WordPress Version >=3.4 5.5.3 Pass
WordPress Memory Limit >=64M 40M Warning
MultiSite Disabled =true true Pass
Méthode FileSystem = direct direct Pass
Réglages PHP
PHP Version >=5.6 7.2.18 Pass
Mode PHP Safe désactivé Arrêt
PHP Max Execution Time >=30 seconds 30 Pass
PHP Max Input Time >=30 seconds 60 Pass
PHP Memory Limit >=128M (256M+ best for big backups) 256M Pass
PCRE Backtracking Limit >=10000 1000000 Pass
PHP Upload Max Filesize >=2M (2MB+ best for upload of big plugins) 16M Pass
PHP Post Max Size >=2M (2MB+ best for upload of big plugins) 8M Pass
SSL Extension Enabled =true true Pass
SSL Warnings = empty Pass
cURL Extension Enabled =true true Pass
cURL Timeout >=300 seconds 60 Warning
cURL Version >=7.18.1 7.35.0 Pass
cURL SSL Version >=OpenSSL/0.9.8l OpenSSL/1.0.1f Pass
Réglages MySQL
MySQL Version >=5.0 5.5.62-0ubuntu0.14.04.1 Pass
Information sur l’archive de sauvegarde
ZipArchive enabled in PHP =true true Pass
Tar GZip supported =true true Pass
Tar BZip2 supported =true true Pass
Informations du serveur
Répertoire racine WordPress /var/www/vhosts/domain.tld/httpdocs/
Nom du serveur domain.tld
Logiciel du serveur nginx/1.14.2
Système d’exploitation Linux
Architecture 64 bit
Adresse IP du serveur 188.165.73.165
Protocole du serveur HTTP/1.1
Hôte HTTP www.domain.tld
HTTPS Arrêt
Connexion automatique du serveur Corps de réponse HTTP non attendu :
Agent utilisateur Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.193 Safari/537.36
Port du serveur 80
Interface de passerelle CGI/1.1
Utilisation de la mémoire 85.56 MB
URL complète http://www.domain.tld/wp-admin/plugins.php
Temps de requête 1606065682
Accepter le contenu text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,/;q=0.8,application/signed-exchange;v=b3;q=0.9
Jeu de caractère accepté pour le contenu N/D
Exécution actuelle du nom de chemin du script /var/www/vhosts/domain.tld/httpdocs/wp-admin/options-general.php
URI de page courante /wp-admin/options-general.php?page=mainwp_child_tab
Adresse distante 82.37.11.178
Hôte distant N/A
Port distant 52916
Information PHP
PHP autorise les URLs fopen Marche
Support PHP Exif Oui ( V7.2.)
Support PHP IPTC Oui
Support PHP XML Oui
Fonctions PHP désactivées opcache_get_status,
Extensions PHP chargées Core, PDO, PDO_ODBC, Phar, Reflection, SPL, SimpleXML, Zend OPcache, bcmath, bz2, calendar, cgi-fcgi, ctype, curl, date, dba, dom, enchant, exif, fileinfo, filter, ftp, gd, gettext, gmp, hash, iconv, imagick, imap, intl, ionCube Loader, json, ldap, libxml, mbstring, mysqli, mysqlnd, odbc, openssl, pcre, pdo_mysql, pdo_pgsql, pdo_sqlite, pgsql, posix, pspell, redis, session, soap, sockets, sodium, sqlite3, standard, sysvmsg, sysvsem, sysvshm, tidy, tokenizer, xml, xmlreader, xmlrpc, xmlwriter, xsl, zip, zlib
Iinformation MySQL
Mode MySQL Non défini
Encodage client MySQL utf8
WordPress PLUGINS
Akismet Anti-Spam 4.1.7 Inactif
Auto Thickbox 3.5 Inactif
Contact Form 7 5.3 Active
Custom Sidebars 3.2.3 Active
Easy FancyBox 1.8.18 Active
Event Calendar 3.1.4 Inactif
Event Calendar Widget 3.1.4 Inactif
Google Universal Analytics 2.4.3 Active
Hello Dolly 1.7.2 Inactif
ICS Calendar v1.6.8 Inactif
Limit Login Attempts 1.7.1 Active
MainWP Child 4.1.2 Active
NextGEN Gallery 3.3.20 Active
pageMash 1.3.0 Inactif
postMash 1.2.0 Inactif
Really Simple CAPTCHA 2.0.2 Active
Themify Portfolio Post 1.1.5 Active
Themify Updater 1.2.7 Active
UpdraftPlus - Backup/Restore 1.16.36 Active
Wordfence Security 7.4.12 Active
WP CODA 1.0 Inactif
WPML Multilingual CMS 2.0.4.1 Inactif
WP STAGING 2.7.8 Active