RE: Unable to create alert rule
[quote user="plotiv"]
I can confirm the user is able to create alerts on this page.
To clarify, the user can (now) create alerts, but is unable to specify the parameters of a custom alert on the Open purchase order lines as shown below. Is this further related to privileges/roles? If so, how can I find out which is the correct role to apply to the user? Thank you.

[/quote]
Does the user have full rights to the purchase lines? A security restriction here could apply. You need access to the trigger points to create an alert, if you dont you cannot create the alert.
What you could do is create an alert for this from an admin user and send it to the Power Platform to then email the user, a pain, but if they dont have the security to do it, they cannot do what they are trying to do.