Whenever I hear that something works from the command line but doesn't work from the browser, I think, "Permissions". People tend to forget that when they are executing a CGI script from the browser, the script runs under the permissions of whatever userid is set up in the web server (often 'nobody' or 'webuser'). So (say, for example, when connecting via SSH) it is quite a different thing for [id://kpaxian25] to attempt an SSH connection to a remote machine than it is for 'webuser' (or whoever) to attempt the same SSH connection. It is possible that there are some keys that need to be applied to webuser's .ssh directory to permit passwordless SSH authentication.