![How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base](https://support.plesk.com/hc/article_attachments/12377512670103/Screenshot_2019-01-21_SSL_TLS_Certificates_-_Plesk_Onyx_17_8_11_1___1_.png)
How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base
![How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base](https://support.plesk.com/hc/article_attachments/12377561548055/Screenshot_2019-03-26_SSL_TLS_Certificates_-_Plesk_Onyx_17_8_11_1_.png)
How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base
![How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base](https://support.plesk.com/hc/article_attachments/12377561527447/Screenshot_2019-03-26_Tools_Settings_-_Plesk_Onyx_17_8_11.png)
How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base
![How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base](https://support.plesk.com/hc/article_attachments/12377561320727/Screenshot_2019-03-26_Secure_Plesk_With_a_Let_s_Encrypt_Certificate_-_Plesk_Onyx_17_8_11.png)
How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base
![How to configure a secure connection when setting up a Plesk email account in an email client - Support Cases from Plesk Knowledge Base How to configure a secure connection when setting up a Plesk email account in an email client - Support Cases from Plesk Knowledge Base](https://support.plesk.com/hc/article_attachments/12377513744791/Screenshot_2018-09-17_SSL_TLS_Certificates_-_Plesk_Onyx_17_8_11.png)
How to configure a secure connection when setting up a Plesk email account in an email client - Support Cases from Plesk Knowledge Base
Mail client shows warning connecting to Plesk mail server: the server to which you are connected uses a security certificate that can not be verified. The main destination name is not valid -
![How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) - Support Cases from Plesk Knowledge Base](https://support.plesk.com/hc/article_attachments/12377512423063/Screenshot_2019-03-26_SSL_TLS_Certificates_-_Plesk_Onyx_17_8_11.png)