Request for Assistance – SMTP Mail & MX Record IP Resolution Issue and Live backup setup another server

Experiencing issues with SMTP mail delivery and MX record resolution for our dedicated server. Specifically, the IP address associated with our mail server is not resolving correctly, which is affecting outgoing and incoming mail flow... (Budget: ₹600 - ₹1500 INR, Jobs: DNS, Email Handling, Linux, Network Security, SMTP, System Admin, TeamViewer, Technical Support, Troubleshooting, Web Hosting)