RAID 1 not auto rebuilding

I have a PE 820 with a PERCH710p adapter.

My raid 1 had a drive die. When I put the replacement in, it is not rebuilding automatically as expected.

Instead, if I click on virtual disks, I see the OS disk is degraded and I have replace member disk as an option.

I have never experienced this before. A little help is appreciated, the thought of our VM host box dying is making me sweat.

Thanks!