[IMP] iot: add documentation regarding HTTPS certificate

Also include details/troubleshoot/solutions for redundant
support issues:
 - Error code details for HTTPS certificate generation
   (see: https://github.com/odoo/odoo/pull/114993 )
 - DNS issue with HTTPS domain

 OPW-3227004

closes odoo/documentation#3818

Signed-off-by: Zachary Straub (zst) <zst@odoo.com>

content/applications/productivity/iot/config.rst

@@ -10,5 +10,6 @@ Configuration
 
    config/connect
    config/pos
+   config/https_certificate_iot
    config/flash_sdcard
    config/troubleshooting

content/applications/productivity/iot/config/https_certificate_iot.rst

@@ -0,0 +1,260 @@
+.. _iot/https_certificate_iot:
+
+=======================
+HTTPS certificate (IoT)
+=======================
+
+What is HTTPS?
+==============
+
+*Hypertext Transfer Protocol Secure* (HTTPS) is the secure version of *Hypertext Transfer Protocol*
+(HTTP), which is the primary protocol used to send data back and forth between a web browser and a
+website. :abbr:`HTTPS (Hypertext Transfer Protocol Secure)` is encrypted in order to increase the
+security of data transfer.
+
+:abbr:`HTTPS (Hypertext Transfer Protocol Secure)` uses an encryption protocol to encrypt
+communications. The protocol is called *Transport Layer Security* (TLS), although formerly it was
+known as *Secure Sockets Layer* (SSL).
+
+:abbr:`HTTPS (Hypertext Transfer Protocol Secure)` occurs based upon the transmission of :abbr:`TLS
+(Transport Layer Security)`/:abbr:`SSL (Secure Sockets Layer)` certificates, which verify that a
+particular provider is who they say they are.
+
+.. note::
+   In this documentation and throughout Odoo the term "HTTPS certificate" will be used to define the
+   fact that the :abbr:`SSL (Secure Sockets Layer)` certificate is valid and allows a :abbr:`HTTPS
+   (Hypertext Transfer Protocol Secure)` connection.
+
+Why is it needed?
+-----------------
+
+In order to communicate with certain network devices (in particular for payment terminals), the
+usage of :abbr:`HTTPS (Hypertext Transfer Protocol Secure)` is mandatory. If the :abbr:`HTTPS
+(Hypertext Transfer Protocol Secure)` certificate isn't valid, some devices won't be able to
+interact with the :abbr:`IoT (Internet of Things)` Box.
+
+How to obtain a Hypertext Transfer Protocol Secure (HTTPS) certificate
+======================================================================
+
+The generation of the :abbr:`HTTPS (Hypertext Transfer Protocol Secure)` certificate is automatic.
+
+The :abbr:`IoT (Internet of Things)` Box will send a specific request to `<https://www.odoo.com>`_
+which will send back the :abbr:`HTTPS (Hypertext Transfer Protocol Secure)` certificate if the
+:abbr:`IoT (Internet of Things)` box and database are eligible.
+
+.. _iot/iot-eligibility:
+
+Internet of Things (IoT) eligibility
+------------------------------------
+
+ #. The database should be a **production** instance. The database instance should not be a copy, a
+    duplicate, a staging, or a development environment.
+ #. The Odoo subscription must:
+
+     - Have an :guilabel:`IoT Box Subscription` line.
+     - :guilabel:`Status` must be :guilabel:`In Progress`.
+
+    If the subscription is linked to a `<https://www.odoo.com>`_ portal user check the information
+    on the portal subscription page.
+
+    .. figure:: https_certificate_iot/sub-example-in-progress.png
+       :align: center
+       :alt: Odoo.com portal subscriptions filtered by "in progress".
+
+       In this case, both subscriptions are considered "in progress" as the :guilabel:`Filter By\:
+       In Progress` was used.
+
+    .. note::
+       If the subscription is in question, contact the database's Account Manager or Partner
+       regarding the matter.
+
+Troubleshooting Hypertext Transfer Protocol Secure (HTTPS) certificate errors
+=============================================================================
+
+If anything goes wrong during the process of the "HTTPS certificate" generation or reception, a
+specific error will code be given on the :abbr:`IoT (Internet of Things)` box home page.
+
+.. tip::
+   Accessing the :abbr:`IoT (Internet of Things)` box homepage will check for the presence of the
+   "HTTPS certificate" and will attempt its generation if it is missing. As such, if there is an
+   error on the :abbr:`IoT (Internet of Things)` box home page, refresh the :abbr:`IoT (Internet of
+   Things)` home page to see if the error disappears.
+
+`ERR_IOT_HTTPS_CHECK_NO_SERVER`
+-------------------------------
+
+Reason:
+    The configuration regarding the server is missing. In other words, the Odoo instance is not
+    connected with the IoT box.
+
+Solution:
+    Ensure that the server is configured.
+
+.. seealso::
+   :doc:`/applications/productivity/iot/config/connect`
+
+`ERR_IOT_HTTPS_CHECK_CERT_READ_EXCEPTION`
+-----------------------------------------
+
+Reason:
+    An unhandled error happened when trying to read the existing :abbr:`HTTPS (Hypertext Transfer
+    Protocol Secure)` certificate.
+
+Solution:
+    Ensure that the :abbr:`HTTPS (Hypertext Transfer Protocol Secure)` certificate file is readable.
+
+`ERR_IOT_HTTPS_LOAD_NO_CREDENTIAL`
+----------------------------------
+
+Reason:
+    The contract and/or database :abbr:`UUID (Universal Unique Identifier)` is missing.
+
+Solution:
+    Ensure that both values are configured as intended. To modify them, go to the :abbr:`IoT
+    (Internet of Things)` box home page, and navigate to :guilabel:`Credential`.
+
+`ERR_IOT_HTTPS_LOAD_REQUEST_EXCEPTION`
+--------------------------------------
+
+Reason:
+    An unexpected error happened when the :abbr:`IoT (Internet of Things)` box tried to reach
+    `<https://www.odoo.com>`_. The causes are likely due to the network
+    infrastructure/configuration:
+
+     - The :abbr:`IoT (Internet of Things)` box does not have access to internet.
+     - The network does not allow the :abbr:`IoT (Internet of Things)` box to communicate with
+       `<https://www.odoo.com>`_. This may be due to network devices preventing the communication
+       (firewalls, etc.) or the network configuration (:abbr:`VPN (Virtual Private Network)`,
+       etc.).
+
+    .. note::
+       More information regarding the error that occurred can be found in the full request
+       exception details, which are in the :abbr:`IoT (Internet of Things)` box logs.
+
+Solution:
+    .. warning::
+       Consult with your system or network administrator should this issue arise. This error code
+       depends on the network infrastructure and goes beyond :doc:`Odoo support's service scope
+       </services/support/what_can_i_expect>`.
+
+`ERR_IOT_HTTPS_LOAD_REQUEST_STATUS`
+-----------------------------------
+
+Reason:
+    The IoT-box was able to reach `<https://www.odoo.com>`_ but received an unusual
+    `HTTP response (status codes)
+    <https://developer.mozilla.org/en-US/docs/Web/HTTP/Status>`_.
+
+    This error code will also give the HTTP response status codes. For example, if the error reads
+    `ERR_IOT_HTTPS_LOAD_REQUEST_STATUS 404` it means that the page returned a 404 error, which is
+    the "Page Not Found" code.
+
+Solution:
+    Check if `<https://www.odoo.com>`_ is down using a web browser, as it's possible that it is down
+    due to maintenance.
+
+     - If `<https://www.odoo.com>`_ is down due to maintenance, unfortunately there is nothing that
+       can be done but instead wait for it to recover.
+     - If `<https://www.odoo.com>`_ is not down due to maintenance, open a `support ticket
+       <https://www.odoo.com/help>`_ on the matter. Ensure that the 3 digits status code next to the
+       code error is included in the support ticket.
+
+`ERR_IOT_HTTPS_LOAD_REQUEST_NO_RESULT`
+--------------------------------------
+
+Reason:
+    The :abbr:`IoT (Internet of Things)` box was able to reach `<https://www.odoo.com>`_ but it
+    refused to deliver the :abbr:`HTTPS (Hypertext Transfer Protocol Secure)` certificate.
+
+Solution:
+    Ensure that the :abbr:`IoT (Internet of Things)` box and database are eligible for a
+    certificate: :ref:`Internet of Things (IoT) eligibility <iot/iot-eligibility>`.
+
+How to ensure that the HTTPS certificate is correct
+===================================================
+
+If the certificate has been applied successfully, a new :abbr:`HTTPS (Hypertext Transfer Protocol
+Secure)` :abbr:`URL (Uniform Resource Locator)` for the :abbr:`IoT (Internet of Things)` box ending
+with `.odoo-iot.com` will appear on the Odoo database, inside of the :menuselection:`IoT`
+application on that specific device's form.
+
+.. image:: https_certificate_iot/odoo-new-domain.png
+   :align: center
+   :alt: Odoo IoT app IoT box with .odoo-iot.com domain.
+
+When navigating to the :abbr:`URL (Uniform Resource Locator)` in a browser a secured :abbr:`HTTPS
+(Hypertext Transfer Protocol Secure)` connection will be established.
+
+.. figure:: https_certificate_iot/secured-connection.png
+   :align: center
+   :alt: Example of valid SSL certificate details on the browser.
+
+   Padlock in Chrome on Windows 10 attesting the fact that the connection is secured in :abbr:`HTTPS
+   (Hypertext Transfer Protocol Secure)`.
+
+The IoT-box homepage will now display an `OK` status next to `HTTPS certificate`. The
+drop-down menu icon, when clicked, will reveal information regarding the certificate.
+
+.. image:: https_certificate_iot/status-ok.png
+   :align: center
+   :alt: IoT box homepage with HTTPS certificate OK status.
+
+Domain Name System (DNS) issue
+==============================
+
+If the :abbr:`IoT (Internet of Things)` box can be accessed from its :abbr:`IP (Intrernet Protocol)`
+address but not the Odoo assigned domain: `.odoo-iot.com`; then the :abbr:`IoT (Internet of Things)`
+box is likely running into a :abbr:`DNS (Domain Name System)` issue. On some browsers, it will give
+an error code mentioning :abbr:`DNS (Domain Name System)` (like `DNS_PROBE_FINISHED_NXDOMAIN`).
+
+These :abbr:`DNS (Domain Name System)` issues may appear as the following in different browsers:
+
+.. tabs::
+
+   .. tab:: Chrome
+
+      .. figure:: https_certificate_iot/dns-chrome.png
+         :align: center
+         :alt: DNS issue on Chrome browser on Windows 10.
+
+         DNS issue on Chrome browser on Windows 10.
+
+
+   .. tab:: Firefox
+
+      .. figure:: https_certificate_iot/dns-firefox.png
+         :align: center
+         :alt: DNS issue on Firefox browser on Windows 10.
+
+         DNS issue on Firefox browser on Windows 10.
+
+   .. tab:: Edge
+
+      .. figure:: https_certificate_iot/dns-edge.png
+         :align: center
+         :alt: DNS issue on Edge browser on Windows 10.
+
+         DNS issue on Edge browser on Windows 10.
+
+
+Domain Name System (DNS) issue solution
+---------------------------------------
+
+#. Should the router allow the :abbr:`DNS (Domain Name System)` to be manually changed, change the
+   DNS to use `Google DNS <https://developers.google.com/speed/public-dns>`_.
+#. If your router doesn't allow for this, then a change will need to be made on the :abbr:`DNS
+   (Domain Name System)` settings of each of the devices using `Google DNS
+   <https://developers.google.com/speed/public-dns>`_. This will need to occur on **every** device
+   that plans to interact with the :abbr:`IoT (Internet of Things)` box (e.g. computer, tablet or
+   phone). The individual device configuration processes can be found on the website of the
+   device's manufacturer.
+
+   .. note::
+      Other :abbr:`IoT (Internet of Things)` devices such as payment terminals likely won't need
+      their :abbr:`DNS (Domain Name System)` settings changed as they are already configured with
+      custom :abbr:`DNS (Domain Name System)`.
+
+   .. warning::
+      Consult with your system or network administrator should this issue arise. This error code
+      depends on the network infrastructure, and it goes beyond :doc:`Odoo support's service scope
+      </services/support/what_can_i_expect>`.