Hello @Anonymous ,
if I have understood correctly your requirement, please follow these steps:
1. Initialize a String variable:

2. Send an HTTP request:

3. Add a "Parse JSON" action:
- Content: Body grabbed from previous action;
- Schema: run the flow, copy the "Send an HTTP request" outputs and paste it in the "Generate from sample" section.

4. Generate an "Apply to each" control, select the "value", grabbed from the "Parse JSON" action in the 2Select an output from previous steps" field:

5. Within the "Apply to each" control, add an "Append to string variable" action, putting the "mail" value got from the "Parse JSON" action. I've appended the variable in the following way just to see in an easier way the email in the email body:
- @{items('Apply_to_each')?['mail']}<br>
6. Outside the "Apply to each" loop, add the Outlook "Send an email (V2)" action and put the variable in the email body:

Here the full flow:

Here the output:

Please let me know if the issue is fixed.
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Marco