An AR2831 on the current network worked well with the configured SSH. For some reasons, the client formats the flash and restores the configuration according to the configuration file manually, but SSH does not work.
Re-run the rsa local-key-pair create command to generate the key pair.
When configuring SSH, you need to run the rsa local-key-pair create to generate a local key pair and store the key pair in the flash, and the command is not saved. When the flash is formatted, the key is lost. As a result, SSH cannot work normally.