Help Our site to pass PCI compliance Scan

We have moved server to a cloud based hosting service at Siteground. Since moving we have failed the PCI compliance scan. We have four medium severity issues that need fixing to pass the scan

In Brief summary these are:
CGI
HTTP Security Header Not Detected
443 / tcp
35.214.1.128

Database
Database Instance Detected
5432 / tcp 35.214.1.128 Requires Details

Database
Database Instance Detected 3306 / tcp 35.214.1.128

Mail services Mail Server Accepts Plaintext Credentials
25 / tcp 35.214.1.128

We need this issue fixed as soon as possible.

Please advise.