Currently I am unable to assign opsgenie alerts in Slack to users.
When I click "Assign" I am given a dropdown of users to choose from. All of my slack users show up in the dropdown. I will attempt to assign the alert to a user who is also an opsgenie user and I receive the message "This user does not exist in Opsgenie"

These are the settings for our Slack Integration

I was unable to find any other references to this error online. All help is appreciated!