Troubleshooting
===============

Cannot Connect via SSH
----------------------

Check network connectivity:

.. code-block:: bash

   ping server.example.edu

Verify SSH access:

.. code-block:: bash

   ssh username@server.example.edu

Common causes:

* Incorrect username.
* Incorrect hostname.
* Missing SSH key.
* Firewall restrictions.

Permission Denied
-----------------

Verify ownership:

.. code-block:: bash

   ls -l

Check permissions:

.. code-block:: bash

   chmod 700 ~/.ssh
   chmod 600 ~/.ssh/authorized_keys

Disk Quota Exceeded
-------------------

Check usage:

.. code-block:: bash

   du -sh ~

Check quota:

.. code-block:: bash

   quota -s

Job Stuck in Queue
------------------

Inspect queue information:

.. code-block:: bash

   squeue -u username

Inspect job details:

.. code-block:: bash

   scontrol show job JOB_ID

Possible causes:

* Insufficient resources available.
* Partition restrictions.
* Time limit too large.
* Memory request too large.

Jupyter Does Not Start
----------------------

Verify installation:

.. code-block:: bash

   jupyter --version

Check for occupied ports:

.. code-block:: bash

   netstat -tulpn | grep 8888

Try another port:

.. code-block:: bash

   jupyter lab --port=8889

Collecting Diagnostic Information
---------------------------------

Before contacting administrators, collect:

* Username.
* Command executed.
* Full error message.
* Date and time.
* Relevant log files.