Hxcore.ol ~repack~ Online

A standard Message-ID looks like unique-string@domain.com . In cases involving hxcore.ol, you might see a format such as *@hxcore.ol .

Are you seeing in your server logs or a specific email header ? Gmail assigning Message-IDs with two different domains hxcore.ol

: Systems use these IDs to group messages together in your inbox. If the ID changes or is formatted incorrectly, it can sometimes cause threads to break, leading to fragmented conversations. Technical Implications for Admins A standard Message-ID looks like unique-string@domain

: Some users have noted that initial messages in a conversation thread may carry the hxcore.ol ID, while replies might revert to standard domains like mail.gmail.com . Gmail assigning Message-IDs with two different domains :

: Using a dedicated domain like hxcore.ol helps infrastructure providers monitor delivery rates and manage bounce-backs without cluttering the client's primary domain reputation. Why Do I See This in My Email?