Etcher won't read USB/SSD card on Mac

I’m using a Mac. Downloaded Umbrel. Trying to flash it to an SSD card on a USB drive. When I select target it’s not recognizing the SSD. It only recognizes my Mac’s hard drives. how can I get it to find my SSD card to flash it?

Sorry for the delayed reply @Heather, and welcome to the Forums!

Leaving Etcher out of the equation, does the Mac itself recognize the SSD? Does it show up in the “Disk Utility”? (Finder → Utilities → Disk Utility)

I am curious if the drive is not even being recognized by the OS, in which case Etcher won’t find it either. Let us know, thanks!