Syncing campaigns and statistics to CRM - only working on some campaigns?

Syncing campaigns and statistics to CRM - only working on some campaigns?

Hi,

I have an issue regarding the sync. I have many automations in Campaigns - where all mails individually inside these automations, are getting synced to CRM. However, I also have some mails that I can see is being sent to contacts, are NOT synced to CRM? So I can't see entire campaigns have been sent to contacts in CRM, which I KNOW have received the campaigns.

I can clearly see the contacts have received the campaigns in Zoho Campaigns though.

What can be the cause of some automations and mails are synced, but not others?

I hope for a fast response.