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) – Plesk Help Center How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center](https://support.plesk.com/hc/article_attachments/360029693474/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) – Plesk Help Center
Choose Let's Encrypt in Plesk and Enjoy with Secured Data | Web Hosting Forum - Review - Community & Resources
![How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center](https://support.plesk.com/hc/article_attachments/360029677374/Screenshot_2019-03-26_SSL_TLS_Certificates_-_Plesk_Onyx_17_8_11.png)
How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center
![How do I enable Let's encrypt Free SSL Certificate for my domain in Plesk? - Knowledgebase - AccuWebHosting How do I enable Let's encrypt Free SSL Certificate for my domain in Plesk? - Knowledgebase - AccuWebHosting](https://manage.accuwebhosting.com/kb-images/How-do-I-enable-Lets-encrypt-Free-SSL-Certificate-for-my-domain-in-Plesk/01-click-on-website-domains-option-in-plesk.png)
How do I enable Let's encrypt Free SSL Certificate for my domain in Plesk? - Knowledgebase - AccuWebHosting
![How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center](https://support.plesk.com/hc/article_attachments/360029679194/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) – Plesk Help Center
![How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center](https://support.plesk.com/hc/article_attachments/360030512173/Screenshot_2019-03-26_Add_SSL_TLS_Certificate_-_Plesk_Onyx_17_8_11.png)
How to secure a Plesk mail server with an SSL certificate (Let's Encrypt / other certificate authorities) – Plesk Help Center
RESOLVED]: Error "TLS Negotiation failed, the certificate doesn't match the host" in Gmail | Web Hosting Forum - Review - Community & Resources
![How to configure a secure connection when setting up a Plesk email account in an email client – Plesk Help Center How to configure a secure connection when setting up a Plesk email account in an email client – Plesk Help Center](https://support.plesk.com/hc/article_attachments/360023314534/Screenshot_2018-09-17_SSL_TLS_Certificates_-_Plesk_Onyx_17_8_11.png)