Skip to content
  • Solutions
    By Role
    • For Developers
    • For Content Managers
    • For Agencies
    • For IT Admins
    • For Web Hosters
    • For Developers
    • For Content Managers
    • For Agencies
    • For IT Admins
    • For Web Hosters
    By Infrastructure
    • Overview
    • AWS
    • Microsoft Azure
    • Alibaba Cloud
    • Google Cloud Platform
    • Vultr
    • Overview
    • AWS
    • Microsoft Azure
    • Alibaba Cloud
    • Google Cloud Platform
    • Vultr
    • Digital Ocean
    • Linode
    • Upcloud
    • Oracle
    • OVH
    • Digital Ocean
    • Linode
    • Upcloud
    • Oracle
    • OVH
  • Product
    • Plesk Features
    • Plesk Editions
    • What’s new
    • Pricing
    • Roadmap
    • Lifecycle Policy
    • Extensions Catalogue
  • Pricing
  • Extensions
    Featured Extensions
    • SocialBee
    • WP Toolkit
    • Sitejet Builder for Plesk
    • SEO Toolkit
    • Joomla! Toolkit
    • Premium Email
    • Email Security
    • SocialBee
    • WP Toolkit
    • Sitejet Builder for Plesk
    • SEO Toolkit
    • Joomla! Toolkit
    • Premium Email
    • Email Security
    Bundles and packs:
    • Business and Collaboration Edition
    • WP pack
    • Hosting pack
    • Power pack
    • Language pack
    • Business and Collaboration Edition
    • WP pack
    • Hosting pack
    • Power pack
    • Language pack

    See all Extensions

  • For Partners
    • Plesk Contributor Program
    • Plesk Partner Program
    • Affiliate program
    • Plesk University
  • Help Center
    • Documentation
    • Professional Services
    • Support
    • Contact Us
    • Wiki
    • Forum
  • Plesk 360 login
  • Free Trial
  • Pricing
  • Solutions
    • By Role
      • For Developers
      • For Content Managers
      • For Agencies
      • For IT Admins
      • For Web Hosters
    • By Infrastructure
      • Overview
      • Plesk on Amazon Web Services (AWS & Lightsail)
      • Microsoft Azure
      • Alibaba Cloud
      • Google Cloud Platform
      • Vultr
      • DigitalOcean
      • Linode
      • UpCloud
      • Oracle
      • OVH
  • Products
  • Pricing
  • Extensions
    • Featured Extensions
      • SocialBee
      • WP Toolkit
      • Sitejet Builder for Plesk
      • SEO Toolkit
      • Joomla! Toolkit
      • Premium Email
      • Email Security
    • Bundles and packs:
      • Business and Collaboration Edition
      • WP pack
      • Hosting pack
      • Power pack
      • Language pack
      • See all Extensions
  • For Partners
    • Plesk Contributor Program
    • Plesk Partner Program
    • Affiliate Program
    • Plesk University
  • Help Center
    • Documentation
    • Professional Services
    • Support
    • Contact Us
    • Wiki
    • Forum
  • Plesk 360 login
  • Free Trial
  • Pricing
  • Solutions
    • By Role
      • For Developers
      • For Content Managers
      • For Agencies
      • For IT Admins
      • For Web Hosters
    • By Infrastructure
      • Overview
      • Plesk on Amazon Web Services (AWS & Lightsail)
      • Microsoft Azure
      • Alibaba Cloud
      • Google Cloud Platform
      • Vultr
      • DigitalOcean
      • Linode
      • UpCloud
      • Oracle
      • OVH
  • Products
  • Pricing
  • Extensions
    • Featured Extensions
      • SocialBee
      • WP Toolkit
      • Sitejet Builder for Plesk
      • SEO Toolkit
      • Joomla! Toolkit
      • Premium Email
      • Email Security
    • Bundles and packs:
      • Business and Collaboration Edition
      • WP pack
      • Hosting pack
      • Power pack
      • Language pack
      • See all Extensions
  • For Partners
    • Plesk Contributor Program
    • Plesk Partner Program
    • Affiliate Program
    • Plesk University
  • Help Center
    • Documentation
    • Professional Services
    • Support
    • Contact Us
    • Wiki
    • Forum
  • Plesk 360 login
  • Free Trial
Plesk 360 login
Free Trial

Knowledge Base

Unable to add a server to Plesk 360 with the error: unable to verify the first certificate

 
360platform 360plesk 360serverserver inventory

Symptoms

  • Unable to add a server to Plesk 360 with the error:

    unable to verify the first certificate

  • Online SSL checkers (such as Qualsys SSL Labs, SSL Shopper) show one of the errors below:

    Intermediate certificate missing


    The certificate is not trusted in all web browsers. You may need to install an Intermediate/chain certificate to link it to a trusted root certificate.


    This server's certificate chain is incomplete

Cause

The certificate consists of 3 parts:

  • *.key file private key;
  • *.crt - certificate itself;
  • *-ca.crt - certificate of Certificate Authority.

The error means the Certificate Authority (ca.crt) part of the certificate is missing.

Resolution

*.key / *.crt / *-ca.crt parts of the certificate should be provided by the corresponding Certificate Authority.

Contact the certificate issuer and ask to provide CA part of the certificate:

  • Comodo
  • IdenTrust
  • Symantec
  • GoDaddy
  • GlobalSign

Rename the existing certificate under Plesk > Tools & Settings > SSL/TLS Certificates > certificate _name > Rename.

Then, install the certificate again. All three parts should be uploaded/filled for the certificate:
mceclip0.png

Additional Information

How to secure a Plesk hostname on port 8443 with an SSL certificate (Let's Encrypt / other certificate authorities)

Tweet
Share
Share
Email
0 Shares
Read the full article
Related Posts

Exploring Plesk’s Added Value Solutions So Far in 2023

Read More »

Unveiling Sitejet Builder: The Perfect Match for Your Effortless Website Creation Needs

Read More »

Dynamic List vs. Active List: A Comprehensive Comparison – Unveiling the Ultimate Winner!

Read More »
Knowledge Base

Not possible to connect server to Plesk 360: The server has an invalid certificate

Read More »

A server shows the error in Plesk 360: Connection error

Read More »

The message “Connection error” appears in Plesk 360 for a server behind Cloudflare

Read More »

Error on adding a server to Plesk 360: The token is invalid possibly because the server time differs from the world time

Read More »

Hosting Wiki

  • Server Redundancy
  • Bare Metal Server
  • Oracle VM Server
  • Server Virtualization Software
  • Windows Server
  • Plesk
  • Web Server
  • DNS Server
  • SSL
X-twitter Linkedin Youtube Reddit Github
  • Product
  • Login
  • Pricing
  • Editions
  • For Partners
  • Partner Program
  • Contributor Program
  • Affiliate Program
  • Plesk University
  • Company
  • Blog
  • Careers
  • Events
  • About Plesk
  • Our Brand
  • Resources
  • User and Admin guides
  • Help Center
  • Migrate to Plesk
  • Contact Us
  • Hosting Wiki
  • Forum
  • Legal
  • Legal
  • Privacy Policy
  • Imprint

© 2025 WebPros International GmbH

Part of the WebPros®  Family