Question how can i Deploy (Ephemeral) Elliptic-Curve Diffie-Hellman or usea 2048-bit or stronger Diffie-Hellm

[elaa]

one of the clients has run a security scan for the site web that I am working on, so he found some issues that i need to fix
these issues are :
FTP Unencrypted Cleartext Login
// solution: Enable FTPS or enforce the connection via the 'AUTH TLS'

SMTP Unencrypted Cleartext Login
//solution: Enable SMTPS or enforce the connection via the 'STARTTLS' command

POP3 Unencrypted Cleartext Login
//solution:
Configure the remote server to always enforce encrypted connections via SSL/TLS with the 'STLS' command

SSL/TLS: Diffie-Hellman Key Exchange Insufficient DH Group Strength Vulnerability...
//solution:
Deploy (Ephemeral) Elliptic-Curve Diffie-Hellman (ECDHE) or use a 2048-bit or stronger Diffie-Hellman group

I have been searching how to apply these solutions so long but I could not find a way if anyone knows how I would be grateful
I am using Plesk onyx, Nginx with a user account