Greetings,
I am using an HTTP POST call (from the Groups section of actions) to forward an event from a group calendar to an individual calendar. The use case is, users can submit events to be Featured, and to submit, they add a group to their meeting invite. Once a new item is added to this group calendar, an approval is triggered. If the item is approved, the meeting is forwarded to an individual shared mailbox service account that we use in our digital signage screens. The connection is done through a separate normal service account.
This is the call that was working just fine for months until today:

So, a POST to https://graph.microsoft.com/v1.0/groups/(groupID)/events/@{triggerOutputs()?['body/id']}/forward
Today, this error started being thrown.

I can't find much on this error, or even this Graph call that I'm using, so I'm reaching out for help here. The service account has been able to do this call for months as I said, and we've now tried giving the service account send as permissions and delegated full access to the event service account. If it's an issue of giving it more time, my account already has had these permissions, and the call no longer works under my account either.
Thank you in advance!