Disconnected: No supported authentication methods available (server sent: publickey, gssapi-with-mic)

When we trying to connect to an Oracle Cloud Linux/UNIX-Like Instance through Open SSH, the SSH client returns one of the following errors:

Issue:

"Disconnected: No supported authentication methods available (server sent: publickey)"
"Disconnected: No supported authentication methods available (server sent: publickey, gssapi-with-mic)"

Fix:

There are multiple issues that could cause such an error, please read below what the troubleshoot steps are for the most common causes.

1. Check that the IP address against which you try to connect is the address of the correct instance. This can be performed either through the Compute Console or the REST API:
Listing Instances in the Compute Console
Retrieving Details of an Instance using the REST API
Note that, unless reserved, the IP addresses of instances could change after reboots: Reserving a Public IP Address

2. Check that a SSH private key is configured in the SSH client you use or it is specified to the SSH/SCP/SFTP command.

3. Check that the SSH client/SSH agent (e.g. WinSCP, PuTTY, Pageant, etc) you use points to the correct directory containing the private SSH keys.

4. Check that the .pem private SSH key file has been converted successfuly to the .ppk format.

5. If you installed a new version of openssh-client or openssh-server, try to erase/purge the already installed version before installing the new one, for example:

sudo yum remove openssh-server
sudo yum -y install openssh-server openssh-clients
or, on some other Linux distros:

sudo apt-get purge openssh-server
sudo apt-get install openssh-server openssh-client
6. If you have another active SSH session/terminal open, check that the SSH daemon is running, by calling "sudo service sshd status" or, on some other distros, "sudo service ssh status". If it's stopped, try to start it.

7. If no other terminal is opened, generally an instance restart should restart the SSH daemon as well. You can also check in the web console whether or not the SSH daemon started during the boot: Viewing the Boot Log of an Instance

Oracle Application R12 forms not opening in Linux

When we are trying to access forms in Oracle apps R12.1 in Linux got the below error.

Error:

Fix:

When you done with the plugin installation, issue about:plugins and check whether your installed jre plugin is showing in mozilla. if it does you can access the forms. 

To know the recommended jre plugin version issue the below : 
grep plugin $CONTEXT_FILE 
<!-- JDK plugins --> 
<sun_plugin_ver oa_var="s_sun_plugin_ver">1.6.0_07</sun_plugin_ver> 
<sun_plugin_type oa_var="s_sun_plugin_type">jdk</sun_plugin_type> 

Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.18) Gecko/20110621 Oracle/3.6-1.0.1.el5_6 Firefox/3.6.18 

Download and install the below : (Make sure you os bit version when you download) http://www.oracle.com/technetwork/java/javase/downloads/java-archive-downloads-javase6-419409.html#jre-6u33-oth-JPR

Install ---> jre-6u33-linux-x64.bin 

Since my operating ssystem were 64 bit we must create soft link to /usr/lib64 folder instead of /usr/lib 
go to /usr/lib64/mozilla/plugins 

Create softlink as below : 
ln -s /home/oracle/jre1.6.0_33/lib/amd64/libnpjp2.so . 

libnpjp2.so -> /oracle/jre1.6.0_33/lib/amd64/libnpjp2.so 

Now you  can able to access the forms in Linux.

error while loading shared libraries: libXtst.so.6: cannot open shared object file: No such file or directory

Error:

Concurrent program error with the following message.

error while loading shared libraries: libXtst.so.6: cannot open shared object file: No such file or directory.

Fix:

Install the following RPM's to resolve the issue.

yum install libXext.x86_64
yum install libXrender.x86_64
yum install libXtst.x86_64

GConf Error: Failed to contact configuration server; some possible causes are that you need to enable TCP/IP networking for ORBi

Error:

GConf Error: Failed to contact configuration server; some possible causes are that you need to enable TCP/IP networking for ORBit, or you have stale NFS locks due to a system crash. See http://projects.gnome.org/gconf/ for information. (Details - 1: Failed to get connection to session: Failed to connect to socket /tmp/dbus-QS6NzEDBEh: Connection refused)

In the /var/log/messages

gconfd (root-21343): Bad permissions 777 on directory /tmp/gconfd-root
gconfd (root-21343): Failed to get lock for daemon, exiting: Directory /tmp/gconfd-root has a problem, gconfd can't use it

Fix:

1.Change permissions to 700  on directory /tmp/gconfd-root
2. Restart the VNC server.