You need to connect server to existing farm in sharepoint. If due to some issue, you disconnected web front-end server from sharepoint farm. After issue resolution, you need to connect web front-end server back to exisiting server farm again.
Install SSL trusted root Intermediate certificate
Install SSL certificate trusted root certificate Intermediate certificate is required on sharepoint servers which is provided by Certification Authority. SSL is a security protocol that establishes a secure connection by providing encrypted connection between server and client, typically between server and client browser. So, its mandatory to install ssl certificate in servers.