Unable to delete restore point in Azure backup

I hope someone can help me because I've been looking for a solution for hours.

I have created a VM in Azure and enabled backup. This morning I deleted the VM, and the recovery service vault I created for my backups.

Deletion of the VM and recovery service vault was successful. However, a restore point collection has been left behind which I cannot delete. When I open the collection I see that there is 1 snapshot present, but I cannot delete it either.

When I remove it I get the following error:

In the log I find the following text:

There is an active shared access signature outstanding for disk restore point

Anyone have any idea what's going wrong?

The problem has been solved with help of support engineers, it was necessary to revoke SAS access of the disk restore point via the following link: https://learn.microsoft.com/en-us/rest/api/compute/disk-restore-point/revoke-access?tabs=HTTP#code-try-0

Unfortunately it was not possible to do this via the Azure portal as the snapshot itself was already deleted.