Hi @Anonymous ,
I have made atest on my side to send an request to an email from the form response and don't have the issue that you mentioend.
The screenshot of the flow as below:
The flow would run successfully as below:

Could you please share the screenshot of the flow run history when it run failed so we could better understand the issue?
Could you please share more details about the error message?
Please make a test on your side to add a "compose" action with the "Manager's email"dynamic content before the approval action to see if the email is correct.
Please let me know if your problem could be solved.
Best regards,
Alice
Community Support Team _ Alice Zhang
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.