Error creating emailed report subscriptions in Sharepoint-integrated SSRS

Anybody who has the rights to run a report in SSRS can set up a subscription, delivering the report to their own email address. However, if you try to deliver the report as an email to somebody else, you might be greeted with this unclear error message:
Reporting Services - other users email address
It reads:

A subscription delivery error has occurred. (rsDeliveryError)
One of the extension parameters is not valid for the
following reason: The account you are using does not
have administrator privileges. A subscription cannot
be created for bob.thompson@mydomain.com.
(rsInvalidExtensionParameter)

I was setting up a subscription in our Sharepoint-integrated SQL Reporting Services site, and was attending to send the report to our shared group email address. I could set it up to deliver to me and I could forward it, but it wasn’t letting me send the email to anybody else’s email address, either inside or outside the organization.

Solution: Grant your user “Create Alerts” and “Manage Alerts” permission

I received this error because I lacked the “Create Alerts” and “Manage Alerts” on the report in question (or folder, or higher up). The error says you need to be an administrator, but doesn’t really tell you what’s wrong with your request – it’s really complaining that you’re delivering an alert to somebody else. Granting those rights to your user account (for that report, or to an object above it so they propagate down to that report) allows you to send the report to any email address you want.

I hope this helps!