Mac not detecting SSD
I'm using an internal ssd on my macbook pro mid 2012. For the last 2 days it has been showing a folder with a question mark icon on start up. I wanted to check if it was a hardware issue and connected my ssd externally with a sata to usb A converter. But now I’m getting a stop sign while booting up. Can anyone help?
MacBook Pro 13″, macOS 10.15