When sending out an Email in a client template, typically from an active record opened in a browser, not all or none of the attachments get sent out.
An error can be seen in the Email logs "Maximum allowed email attachment count exceeded. (max:30). Email sent without one or more of its attachments".
This issue happens in a context where an Email client template are used that dynamically fill in the body of the new Email.
This is unexpected because the system limit set with property "glide.email.outbound.max_attachment_count" is higher than the number of files attached to the Email sent.
Release or Environment
The limit "glide.email.outbound.max_attachment_count" is exceeded because it is not only the number of files manually attached in the Email that counts but also all the embedded tags that point to a sys_attachment record within the Body of the Email client template.
When you take a look at the HTML source of the Email body template, you will see this kind of code: src="/sys_attachment.do?sys_id=545097bcdbexxxxxxx971d9619b6" and this counts toward an attachment.
When pre-filling the templates, make sure not to include logos or other images, otherwise increase the number of total attachments with property "glide.email.outbound.max_attachment_count"