Email (containing a tracking token) will not get promoted to crm by email router if the mail is linked to a closed (read-only) case. This is by design for all crm versions.
However due to this behavior the application has unreliable side effects as a mailing and case platform since not all emails arrive in the application and customer needs to browse their outlook mailboxes for the exceptions.

I would like to modify this behavior.

Ideas Administrator

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