Hi there,
I am facing a big problem with syncing and connecting with my child sites using Plesk. I currently have more than 30 in Plesk and 10 in Cpanel, and the problem seems for some reason to occur only in those using Plesk.
Once I try to sync, I get the error “MainWP Child plugin not detected or could not be reached!” and the site gets disconnected.
In the Custom Event Monitor, I get the following log:
2025-04-21 11:38:26 [aloftmykonos.gr] [aloftmykonos.gr] ::SYNC ERROR:: [MainWP Child plugin not detected or could not be reached! Ensure the MainWP Child plugin is installed and activated on the child site, and there are no security rules blocking requests. If you continue experiencing this issue, check the <a href="https://community.mainwp.com/c/community-support/5" target="_blank">MainWP Community</a> for help.] #0 /home/glocalgr/public_html/wp-content/plugins/mainwp/class/class-mainwp-sync.php(545): MainWP\Dashboard\MainWP_Logger->warning_for_website() #1 /home/glocalgr/public_html/wp-content/plugins/mainwp/class/class-mainwp-sync.php(217): MainWP\Dashboard\MainWP_Sync::sync_information_array() #2 /home/glocalgr/public_html/wp-content/plugins/mainwp/class/class-mainwp-manage-sites-view.php(1882): MainWP\Dashboard\MainWP_Sync::sync_site() #3 /home/glocalgr/public_html/wp-content/plugins/mainwp/pages/page-mainwp-manage-sites-handler.php(153): MainWP\Dashboard\MainWP_Manage_Sites_View::m_reconnect_site() #4 /home/glocalgr/public_html/wp-content/plugins/mainwp/class/class-mainwp-post-site-handler.php(368): MainWP\Dashboard\MainWP_Manage_Sites_Handler::reconnect_site() #5 /home/glocalgr/public_html/wp-includes/class-wp-hook.php(324): MainWP\Dashboard\MainWP_Post_Site_Handler->mainwp_reconnectwp() #6 /home/glocalgr/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters() #7 /home/glocalgr/public_html/wp-includes/plugin.php(517): WP_Hook->do_action() #8 /home/glocalgr/public_html/wp-admin/admin-ajax.php(192): do_action()
2025-04-21 11:38:26 [aloftmykonos.gr] [aloftmykonos.gr] ::fetch_url:: [https://aloftmykonos.gr/] Error: NOMAINWP [data=[hidden response data]]
2025-04-21 11:38:26 [aloftmykonos.gr] [aloftmykonos.gr] ::fetch_url_site:: http status: [415] err: []
2025-04-21 11:38:26 [aloftmykonos.gr] [aloftmykonos.gr] ::fetch_url_site:: Executing handlers
2025-04-21 11:38:25 [aloftmykonos.gr] [aloftmykonos.gr] ::fetch_url_site:: Request to [https://aloftmykonos.gr/wp-admin/admin-ajax.php]
I have had similar problems for over the last 3-4 months , where in some cases the problem was gone temporarily and then reappeared after some updates. But in the last days the problem is consistent and I can not get to connect with any of my child sites using Plesk.
From my research and tests, I always find the HTTP status error 415 to be the problem.
The HTTP 415 Unsupported Media Type client error response status code indicates that the server refused to accept the request because the message content format is not supported. The format problem might be due to the request’s indicated Content-Type or Content-Encoding, or as a result of processing the request message content. Some servers may be strict about the expected Content-Type of requests. For example, sending UTF8 instead of UTF-8 to specify the UTF-8 charset may cause the server to consider the media type invalid.
Just to note that there are no firewall rules on myu child sites servers, no security plugins, and from what it appears in the child sites’ server logs, it seems that the requests coming from the main wp dashboard server never reach the child site server. There is no error of any kind in the logs of my child sites’ servers!
So I believe that it has something to do with the actual request the mainwp dashboard is sending to the servers where my child sites are and using Plesk.
Can someone please help me?
Below, I am also sending my System Report
### WordPress Check Required Detected Status ###
FileSystem Method = direct direct Pass
MultiSite Disabled =true true Pass
WordPress Memory Limit >=64M 256M Pass
WordPress Version >=6.2 6.8 Pass
### PHP Required Detected Status ###
cURL Extension Enabled =true true Pass
cURL Timeout >=300 seconds 60 Warning
cURL Version >=7.29.0 8.12.1 Pass
Function `tmpfile` enabled N/A Enabled Pass
OpenSSL Version >=OpenSSL/1.1.0 OpenSSL/1.1.1w Pass
OpenSSL Working Status Yes Yes Pass
PCRE Backtracking Limit >=10000 1000000 Pass
PHP Allow URL fopen N/A YES
PHP Disabled Functions N/A No functions disabled.
PHP Exif Support N/A YES
PHP IPTC Support N/A YES
PHP Loaded Extensions N/A Core, PDO, PDO_ODBC, Phar, Reflection, SPL, SimpleXML, bcmath, bz2, calendar, ctype, curl, date, dba, dom, enchant, exif, fileinfo, filter, ftp, gd, gettext, gmp, hash, iconv, igbinary, imap, intl, json, ldap, libxml, litespeed, mbstring, msgpack, mysqli, mysqlnd, odbc, openssl, pcntl, pcre, pdo_mysql, pdo_pgsql, pdo_sqlite, pgsql, posix, pspell, readline, redis, session, shmop, snmp, soap, sockets, sqlite3, standard, sysvmsg, sysvsem, sysvshm, tidy, tokenizer, xml, xmlreader, xmlwriter, xsl, zip, zlib
PHP Max Execution Time >=30 seconds 0 Pass
PHP Max Input Time >=30 seconds 300 Pass
PHP Memory Limit >=256M 256M Pass
PHP Post Max Size >=2M 256M Pass
PHP Safe Mode Disabled =true true Pass
PHP Session enabled N/A Enabled Pass
PHP Upload Max Filesize >=2M 256M Pass
PHP Version >=7.4 8.1.32 Pass
PHP XML Support N/A YES
SSL Extension Enabled =true true Pass
SSL Warnings = empty Pass
### MySQL Required Detected Status ###
MySQL Client Encoding N/A utf8
MySQL Mode N/A NOT SET
MySQL Version >=5.0 8.0.42 Pass
### Server Configuration Detected Value ###
Accept Content 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=0.7
Accept-Charset Content N/A
Architecture 64 bit
Gateway Interface
HTTPS ON
Memory Usage 69.21 MB
Operating System Linux
Request Time 1745228511
Server Protocol HTTP/1.1
Server self connect Not expected HTTP response body: 401 Unauthorized
401
Unauthorized
Proper authorization is required to access this resource!
Server Software LiteSpeed
User Agent Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36
### MainWP Dashboard Settings Detected Value ###
Abandoned plugins/themes tolerance 365
Cache control enabled No
Enable Uptime Monitoring Yes
MainWP Dashboard Version Latest: 5.4.0.5 | Detected: 5.4.0.5 Pass
MainWP legacy backups enabled No
Maximum number of pages to return
Maximum number of posts to return
Maximum simultaneous install and update requests3
Maximum simultaneous requests 4
Maximum simultaneous requests per ip1
Maximum simultaneous sync requests 8
Maximum simultaneous uptime monitoring requests (Default: 10)5
Minimum delay between requests 200
Minimum delay between requests to the same ip1000
Number of connected sites 40
Optimize data loading No
Plugin advanced automatic updates enabledYes
Primary Backup System API Backups
REST API enabled No
Site health monitoring enabled No
Theme advanced automatic updates enabledNo
Use WP Cron Yes
WP Core advanced automatic updates enabledNo
### Extensions Version License Status ###
Advanced Uptime Monitor Extension 5.3.1 Active Pass
MainWP Atarim Extension 5.0.1 Active Pass
MainWP Cost Tracker Assistant Extension5.0.5 Active Pass
MainWP Custom Dashboard Extension 5.0.1 Active Pass
MainWP Database Updater Extension 5.0.5 Active Pass
MainWP Maintenance Extension 5.0 Active Pass
MainWP Pro Reports Extension 5.0.6 Active Pass
MainWP SSL Monitor Extension 5.1.1 Active Pass
MainWP Sucuri Extension 5.0.2 Active Pass
MainWP Team Control 5.0.2 Active Pass
MainWP Time Tracker Extension 5.1 Active Pass
MainWP White Label Extension 5.0 Active Pass
WP Activity Log 5.3.4.1
### Plugin Version Status ###
Activity Log for MainWP 2.1.3 Inactive
BackUpWordPress 3.14 Active
Easy WP SMTP 2.10.0 Inactive
MainWP Dashboard 5.4.0.5 Active
MainWP Post SMTP Extension 1.0.3 Inactive
Minimal Coming Soon & Maintenance Mode2.42 Active
WP Activity Log 5.3.4.1 Active
WPS Hide Login 1.9.17.2 Active