@Raj_DB Databricks sends notifications via its internal email service, which often requires the address to be a valid individual mailbox or a distribution list that accepts external mail. If your group email is a Microsoft 365, Please check if 
“Allow external senders” is enabled. No moderation or approval is blocking the email.

Try adding your personal email alongside the group email in the same job:

"email_notifications": {
  "on_failure": ["your.email@company.com", "group@company.com"]
}