No emails from voicemail but it works from backup, module admin, others

I am having a strange issue with VM. It used to be working fine receiving email notifications and text messages, suddenly stopped working and not sure when it stopped working… I can receive the email notifications from Module Admin, Backup and Restore, user management, Intrusion Detection, and UPS but voicemail notification.
I have Sys Admin paid version … I am running FreePBX 13. Please let me know if you need any additional information.

Thank you in advance.