Ensure and document, NOTIFY-EXPIRY notification is send

Hello experts,

I'm getting stuck with the expiration notification right now.

I can define a process and a lead time for roles. When the time is reached, a POV is then generated with MX_OPERATION = NOTIFY-EXPIRY and the process is executed.

Until now I wanted to send the email directly from the process and done.

Unfortunately, however, I notice that the mail dispatch does not always go or is just not guaranteed. Unfortunately there is no possibility to start the process again, because the POV is deleted even if the process fails.

What is the reason for this and can I somehow mark a POV of a failed process so that it is not deleted and I can run my process on it until the message is sent?

Unfortunately we don't use the SAP IDM own mail sender either, but have a central system that maps the mail sending via templates and acts as a mail client. I only call the system via REST API and create an email send job there, so to speak. Unfortunately, this is not yet running so smoothly and I do not know now how I can safely set up this advance notification with the IDM, since we also inform here that accounts are deleted. Thus I need

1. a clear proof that we have sent the mail or if the mail sending went wrong,

the deletion has to be

1. suspended or
2. the mail dispatch is tried until the mail was sent (PVO persist).

How do you ensure mail delivery?

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