Hi @stpa ,
The goal is to send an email if the approval is rejected, correct?
>>To achieve this, In the Condition's "If no" section, add only the "Send an email (V2)" action.
If the Approval Outcome is Rejected, the flow will send an email and end the flow if there is no action configured after that. (Terminate is not necessary here in this case.)

Additionally, the "Apply to each" was added automatically as the "Get Attachments" returns the data in an array (because it may be possible that the list item contains more than one attachment).
If there are more than one attachment, this flow will create one approval for each attachment. If you want to send one approval for all the attachments of an item, please Append all attachments in an array and pass it to Approval.
Try it and let me know if you need further assistance.
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Thank you,
Harsh Deol