A warning is shown while accessing Plesk or webmail: The certificate is not trusted or NET::ERR_CERT_AUTHORITY_INVALID - Support Cases from Plesk Knowledge BaseA warning is shown while accessing Plesk or webmail: The certificate is not trusted or NET::ERR_CERT_AUTHORITY_INVALID - Support Cases from Plesk Knowledge Base
A warning is shown while accessing Plesk or webmail: The certificate is not trusted or NET::ERR_CERT_AUTHORITY_INVALID - Support Cases - Plesk Knowledge Base




Skip to content Contact us: +34 944 58 06 58 Plesk Partner Program Plesk Lifecycle Policy Blog Contact us Plesk 360 Menu Contact us: +34 944 58 06 58 Plesk Partner Program Plesk Lifecycle Policy Blog Contact us Plesk 360 Solutions By Role Developers Content Managers Digital Agencies IT Admins Web Hosters Hyperscalers Menu Developers Content Managers Digital Agencies IT Admins Web Hosters Hyperscalers By Edition Web Admin Edition Web Pro Edition Web Host Edition Business & Collaboration Plesk WordPress Edition Menu Web Admin Edition Web Pro Edition Web Host Edition Business & Collaboration Plesk WordPress Edition By Cloud Amazon Web Services Microsoft Azure Alibaba Cloud GCP Marketplace Vultr DigitalOcean Linode Menu Amazon Web Services Microsoft Azure Alibaba Cloud GCP Marketplace Vultr DigitalOcean Linode Partner Program Exclusive discounts, benefits and exposure to take your business to the next level Become a partner Product Explore Features Everyone Admins & Web Hosters Developers Designers & Agencies Plesk Features Menu Everyone Admins & Web Hosters Developers Designers & Agencies Plesk Features Key Topics WordPress Toolkit SEO Toolkit Plesk eCommerce Toolkit Joomla! Toolkit Plesk Premium Email Plesk Email Security Menu WordPress Toolkit SEO Toolkit Plesk eCommerce Toolkit Joomla! Toolkit Plesk Premium Email Plesk Email Security Feature Packs Business & Collaboration WordPress Pack Hosting Pack Power Pack Language Pack Menu Business & Collaboration WordPress Pack Hosting Pack Power Pack Language Pack Featured Extension WordPress Pack Pricing Extensions Help Center More Careers Events Plesk University FREE TRIAL Solutions By Role Developers Content Managers Digital Agencies IT Admins Web Hosters Hyperscalers By Edition Web Admin Edition Web Pro Edition Web Host Edition Business & Collaboration WordPress Edition By Cloud Amazon Web Services Microsoft Azure Alibaba Cloud GCP Marketplace Vultr DigitalOcean Linode Partner Program Partner Program Product Explore Features Everyone Admins & Web Hosters Developers Designers & Agencies Plesk Features Key Topics WordPress Toolkit SEO Toolkit Plesk eCommerce Toolkit Joomla! Toolkit Plesk Premium Email Plesk Email Security Feature Packs Business & Collaboration WordPress Pack Hosting Pack Power Pack Language Pack Featured Extension Extension Pricing Extensions Help center More Careers Events Webinars Plesk University Blog Plesk Partner Program Contact Us FREE TRIAL Menu Solutions By Role Developers Content Managers Digital Agencies IT Admins Web Hosters Hyperscalers By Edition Web Admin Edition Web Pro Edition Web Host Edition Business & Collaboration WordPress Edition By Cloud Amazon Web Services Microsoft Azure Alibaba Cloud GCP Marketplace Vultr DigitalOcean Linode Partner Program Partner Program Product Explore Features Everyone Admins & Web Hosters Developers Designers & Agencies Plesk Features Key Topics WordPress Toolkit SEO Toolkit Plesk eCommerce Toolkit Joomla! Toolkit Plesk Premium Email Plesk Email Security Feature Packs Business & Collaboration WordPress Pack Hosting Pack Power Pack Language Pack Featured Extension Extension Pricing Extensions Help center More Careers Events Webinars Plesk University Blog Plesk Partner Program Contact Us FREE TRIAL Knowledge Base A warning is shown while accessing Plesk or webmail: The certificate is not trusted or NET::ERR_CERT_AUTHORITY_INVALID domain nameserverwebsiteswebmailurl Symptoms The following error is shown while accessing Plesk or webmail: On Google Chrome: Your connection is not privateNET::ERR_CERT_AUTHORITY_INVALID On Firefox: This Connection is Untrusted(Error code: sec_error_unknown_issuer)Certificate Error: The security certificate presented by this website was issued for a different website's address. This problem might indicate an attempt to fool you or intercept any data you send to the server. On Internet Explorer: There is a problem with this website’s security certificate. On Opera Opera cannot verify the identity of the server "XXXX", due to a certificate problem. The server could be trying to trick you Cause By default, Plesk is using a self-signed certificate that does not have a signature from the trust center.Or, the mismatched certificate was applied. Resolution Note: If Plesk/WebMail is secured via Let’s Encrypt, use hostname/domain name to access it because IP address itself cannot be secured with a valid certificate. In order to avoid the warning, it is required to have a valid SSL certificate. There are several options on how to achieve that: Secure Plesk/domain/WebMail via Let’s Encrypt: For domain/webmail/alias, it is required to go to Websites and Domains > example.com > Let’s Encrypt and proceed with the installation. Details are available in the following article:How to install SSL certificate for a domain in Plesk For securing Plesk/Mail Server, go to Tools & Settings >Skip - to - content - Contact - us: - +34 - 944 - 58 - 06 - 58 - Plesk - Partner - Program - Plesk - Lifecycle - Policy - Blog - Contact - us - Plesk - 360 - Menu - Contact - us: - +34 - 944 - 58 - 06 - 58 - Plesk - Partner - Program - Plesk - Lifecycle - Policy - Blog - Contact - us - Plesk - 360 - Solutions - By - Role - Developers - Content - Managers - Digital - Agencies - IT - Admins - Web - Hosters - Hyperscalers - Menu - Developers - Content - Managers - Digital - Agencies - IT - Admins - Web - Hosters - Hyperscalers - By - Edition - Web - Admin - Edition - Web - Pro - Edition - Web - Host - Edition - Business - & - Collaboration - Plesk - WordPress - Edition - Menu - Web - Admin - Edition - Web - Pro - Edition - Web - Host - Edition - Business - & - Collaboration - Plesk - WordPress - Edition - By - Cloud - Amazon - Web - Services - Microsoft - Azure - Alibaba - Cloud - GCP - Marketplace - Vultr - DigitalOcean - Linode - Menu - Amazon - Web - Services - Microsoft - Azure - Alibaba - Cloud - GCP - Marketplace - Vultr - DigitalOcean - Linode - Partner - Program - Exclusive - discounts - - benefits - and - exposure - to - take - your - business - to - the - next - level - Become - a - partner - Product - Explore - Features - Everyone - Admins - & - Web - Hosters - Developers - Designers - & - Agencies - Plesk - Features - Menu - Everyone - Admins - & - Web - Hosters - Developers - Designers - & - Agencies - Plesk - Features - Key - Topics - WordPress - Toolkit - SEO - Toolkit - Plesk - eCommerce - Toolkit - Joomla! - Toolkit - Plesk - Premium - Email - Plesk - Email - Security - Menu - WordPress - Toolkit - SEO - Toolkit - Plesk - eCommerce - Toolkit - Joomla! - Toolkit - Plesk - Premium - Email - Plesk - Email - Security - Feature - Packs - Business - & - Collaboration - WordPress - Pack - Hosting - Pack - Power - Pack - Language - Pack - Menu - Business - & - Collaboration - WordPress - Pack - Hosting - Pack - Power - Pack - Language - Pack - Featured - Extension - WordPress - Pack - Pricing - Extensions - Help - Center - More - Careers - Events - Plesk - University - FREE - TRIAL - Solutions - By - Role - Developers - Content - Managers - Digital - Agencies - IT - Admins - Web - Hosters - Hyperscalers - By - Edition - Web - Admin - Edition - Web - Pro - Edition - Web - Host - Edition - Business - & - Collaboration - WordPress - Edition - By - Cloud - Amazon - Web - Services - Microsoft - Azure - Alibaba - Cloud - GCP - Marketplace - Vultr - DigitalOcean - Linode - Partner - Program - Partner - Program - Product - Explore - Features - Everyone - Admins - & - Web - Hosters - Developers - Designers - & - Agencies - Plesk - Features - Key - Topics - WordPress - Toolkit - SEO - Toolkit - Plesk - eCommerce - Toolkit - Joomla! - Toolkit - Plesk - Premium - Email - Plesk - Email - Security - Feature - Packs - Business - & - Collaboration - WordPress - Pack - Hosting - Pack - Power - Pack - Language - Pack - Featured - Extension - Extension - Pricing - Extensions - Help - center - More - Careers - Events - Webinars - Plesk - University - Blog - Plesk - Partner - Program - Contact - Us - FREE - TRIAL - Menu - Solutions - By - Role - Developers - Content - Managers - Digital - Agencies - IT - Admins - Web - Hosters - Hyperscalers - By - Edition - Web - Admin - Edition - Web - Pro - Edition - Web - Host - Edition - Business - & - Collaboration - WordPress - Edition - By - Cloud - Amazon - Web - Services - Microsoft - Azure - Alibaba - Cloud - GCP - Marketplace - Vultr - DigitalOcean - Linode - Partner - Program - Partner - Program - Product - Explore - Features - Everyone - Admins - & - Web - Hosters - Developers - Designers - & - Agencies - Plesk - Features - Key - Topics - WordPress - Toolkit - SEO - Toolkit - Plesk - eCommerce - Toolkit - Joomla! - Toolkit - Plesk - Premium - Email - Plesk - Email - Security - Feature - Packs - Business - & - Collaboration - WordPress - Pack - Hosting - Pack - Power - Pack - Language - Pack - Featured - Extension - Extension - Pricing - Extensions - Help - center - More - Careers - Events - Webinars - Plesk - University - Blog - Plesk - Partner - Program - Contact - Us - FREE - TRIAL - Knowledge - Base - A - warning - is - shown - while - accessing - Plesk - or - webmail: - The - certificate - is - not - trusted - or - NET::ERR_CERT_AUTHORITY_INVALID - domain - nameserverwebsiteswebmailurl - Symptoms - The - following - error - is - shown - while - accessing - Plesk - or - webmail: - On - Google - Chrome: - Your - connection - is - not - privateNET::ERR_CERT_AUTHORITY_INVALID - On - Firefox: - This - Connection - is - Untrusted(Error - code: - sec_error_unknown_issuer)Certificate - Error: - The - security - certificate - presented - by - this - website - was - issued - for - a - different - website's - address. - This - problem - might - indicate - an - attempt - to - fool - you - or - intercept - any - data - you - send - to - the - server. - On - Internet - Explorer: - There - is - a - problem - with - this - website’s - security - certificate. - On - Opera - Opera - cannot - verify - the - identity - of - the - server - "XXXX" - - due - to - a - certificate - problem. - The - server - could - be - trying - to - trick - you - Cause - By - default - - Plesk - is - using - a - self-signed - certificate - that - does - not - have - a - signature - from - the - trust - center.Or - - the - mismatched - certificate - was - applied. - Resolution - Note: - If - Plesk/WebMail - is - secured - via - Let’s - Encrypt - - use - hostname/domain - name - to - access - it - because - IP - address - itself - cannot - be - secured - with - a - valid - certificate. - In - order - to - avoid - the - warning - - it - is - required - to - have - a - valid - SSL - certificate. - There - are - several - options - on - how - to - achieve - that: - Secure - Plesk/domain/WebMail - via - Let’s - Encrypt: - For - domain/webmail/alias - - it - is - required - to - go - to - Websites - and - Domains - > - example.com - > - Let’s - Encrypt - and - proceed - with - the - installation. - Details - are - available - in - the - following - article:How - to - install - SSL - certificate - for - a - domain - in - Plesk - For - securing - Plesk/Mail - Server - - go - to - Tools - & - Settings - > -