Testing a new install of Fuse 7.1 on my local workspace. The only change after unzipping the installation is to un-comment the last 2 lines of the users.properties file to enable the admin user. I able to execute the client.bat in Fuse 7.0 in this same scenario.
2018-10-03 08:40:21,426 | DEBUG | ba50d]-nio2-thread-2 | o.a.k.s.s.KarafJaasAuthenticator | 145 - org.apache.karaf.shell.ssh - 4.2.0.fuse-710024-redhat-00002 | User authentication failed with null not available to obtain information from user
javax.security.auth.login.LoginException: null not available to obtain information from user
Workaround:
I think it might be a bug. However, we found a solution to it:
1- Browse to %FUSE_HOME%\system\org\jline\jline. It should contain a folder called "3.6.2". Rename it to "3.6.2.redhat-2"
2- Browse to %FUSE_HOME%\system\org\jline\jline\3.6.2.redhat-2. It should contain a file called "jline-3.6.2.jar". Rename it to "jline-3.6.2.redhat-2.jar"
3- start the client: "bin\client -u admin -p admin"