Added a tip for solving Permission denied error (#133)

user-guide/ssh-access.rst

@@ -26,6 +26,10 @@ Every team member can get access to any of the team's EC2 instances by using the
 
     To get the most of this mode, it's recommended that piu is invoked with the ``--connect`` flag so you get into the instance as soon as the odd host authorizes your request: ``$ piu request-access --interactive --connect``. Alternatively, you can set the ``PIU_CONNECT`` and ``PIU_INTERACTIVE`` environment variables in your shell profile so you can invoke the command with the mentioned features enabled just with: ``$ piu request-access``.
 
+.. Tip::
+
+    If executing a **piu** command results in a message ``Access to host odd-eu-west-1.myteam.example.org for user <myuser> was granted.``, but you get an error ``Permission denied (publickey).``, you can solve this by installing an **ssh-agent** and executing ``ssh-add`` prior to **piu**. 
+
 .. Tip::
 
     Use the ``--clip`` option to copy the output of piu to your clipboard.