The volume primary SSD could not be repaired
Boot to Recovery HD, open in the menubar Utilities > Terminal. Enter df to get the name of your main volume (e.g. "Macintosh HD").

Enter diskutil verifyVolume /Volumes/Vol_name (e.g. diskutil verifyVolume "/Volumes/Macintosh HD").

Then repair the volume with diskutil repairVolume /Volumes/Vol_name.

If no main volume is mounted try diskutil list, determine the disk identifier of the main volume (e.g. disk0s2) and first enter diskutil verifyDisk /dev/disk0 and repair it if necessary with diskutil repairDisk /dev/disk0, then diskutil verifyVolume /dev/disk0s2 and repair it with diskutil repairVolume /dev/disk0s2.

If your SSD has a CoreStorage Logical Volume Group  diskutil repairDisk /dev/disk0 should already repair everything.

If this fails you usually have to use some third-party software like DiskWarrior to repair the volume or restore a (Time Machine-)backup.