Email service does not work properly. If we send then it always deliver in spam box. Also webmail link is not secure. If you can make it secure and also fix these issues then good.
Protecting webmail with SSL certificate is documented here https://docs.plesk.com/en-US/onyx/administrator-guide/website-management/websites-and-domains/advanced-website-security/securing-connections-with-ssltls-certificates/protecting-webmail-with-an-ssltls-certificate.76531/
To solve your mail issue, please browse https://kb.plesk.com for Knowledge Base articles that might have a solution. If you don’t have any luck there, open https://cscontact.plesk.com/ and file a support ticket. We are closing your request as it doesn’t include any software improvement proposal.