First Aid process has failed. If possible back up the data on this volume
The obvious cause is the filesystem or physical media can not make changes so make it reliable. Also, there are many different filesystem types and drives, so be sure your tool supports your OS and Hardware if you don’t try them for free first.
Do you have a backup? If not, do that immediately. You may need recovery software for this if the mechanism is failing. Disconnect the drive immediately if this is the case and buy a new drive that’s larger (or as large) as the drive so you can copy off the files before any more attempts to “fix” it. Sometimes the fix is deleting lost files or corrupt files to make the “filesystem” balance again.

https://www.prosofteng.com/mac-data-recovery I use Data Rescue, but other options exist.

If you want a third party tool to try and fix this, I use Disk Warrior first, then perhaps Drive Genius if I don’t want to just send it to the professionals.

https://www.alsoft.com/
https://www.prosofteng.com/drive-genius-mac-protection-software

If you don’t need to back up the data, just erase the drive entirely. That is free and Apple tools will test if the drive is functioning as part of the erase operation.