1) Add initialization error page; 2) Add connection error page.

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="chromeos">. -->
 <grit-part>
   <message name="IDS_EMPTY_STRING" desc="Empty string, exist only to make code generic. No translation required.">
   </message>
   <!-- Idle logout dialog for retail mode -->
   <message name="IDS_IDLE_LOGOUT_TITLE" desc="Dialog title for the idle logout dialog. Used in retail mode only.">
     Are you still there?
   </message>
@@ skipping 5944 matching lines @@
   </message>
   <message name="IDS_PAIRING_HOST_UPDATING_TEXT" desc="Update progress shown on the host's update page of the 'Chromebox for meeting' setup process.">
     <ph name="DOWNLOADED_AMOUNT_MB">$1<ex>13.7</ex></ph> MB / <ph name="TOTAL_AMOUNT_MB">$2<ex>23</ex></ph> MB downloaded
   </message>
   <message name="IDS_PAIRING_HOST_DONE_TITLE" desc="Title of the final host's page shown when the 'Chromebox for meeting' setup process is finished.">
     Congratulations
   </message>
   <message name="IDS_PAIRING_HOST_DONE_TEXT" desc="Title of the final host's page shown when the 'Chromebox for meeting' setup process is finished.">
     You're all set to continue on to Hangouts
   </message>
-  <message name="IDS_PAIRING_HOST_EROLLMENT_ERROR_NEEDS_RESTART" desc="Text on the host's page of the 'Chromebox for meeting' setup process shown when enrollment attempt is failed.">
-    Chromebox needs to restart...
+  <message name="IDS_PAIRING_HOST_ERROR_NEED_RESTART_TEXT" desc="Text on the host's error page shown when the bootstrapping attampt or 'Chromebox for meeting' setup process is failed.">
+    Please restart the device and try again later.
   </message>
 
   <!-- Strings for the bootstrapping OOBE process -->
   <message name="IDS_HOST_SETUP_BASIC_CONFIGURATION_TITLE" desc="Title of the host's basic configuration setup page during the bootstrapping process.">
     Setup network connection, language, keyboard layout...
   </message>
   <message name="IDS_HOST_SETUP_NETWORK_ERROR_TITLE" desc="Title of the host's network error page during the bootstrapping process.">
     Could not set up network
   </message>
   <message name="IDS_SLAVE_CONFIRMATION_TITLE" desc="Title of the host's confirmation page of the bootstrapping process. 6-digit confirmation code is displayed below.">
     Initialize the connection
   </message>
   <message name="IDS_SLAVE_ENROLL_TITLE" desc="Title of the enroll page of the bootstrapping process.">
     Enroll in your organization
   </message>
   <message name="IDS_SLAVE_ENROLLMENT_IN_PROGRESS" desc="Message shown on the host screen of the bootstrapping process.">
     Enrolling in <ph name="BEGIN_BOLD">&lt;strong&gt;</ph><ph name="DOMAIN_NAME">$1<ex>example.com</ex></ph><ph name="END_BOLD">&lt;/strong&gt;</ph>...
   </message>
   <message name="IDS_SLAVE_ENROLLMENT_ERROR_TITLE" desc="Title of the page shown when enrollment attempt is failed during the bootstrapping process.">
     Unable to enroll
   </message>
-  <message name="IDS_SLAVE_EROLLMENT_ERROR_NEEDS_RESTART" desc="Text on the host's page shown when enrollment attempt is failed during the bootstrapping process.">
-    Please restart the device and try again later.
+  <message name="IDS_PAIRING_HOST_INITIALIZATION_ERROR_TITLE" desc="Title of the host's initialization error page during the bootstrapping process or 'Chromebox for meeting' setup process.">
+    Could not initialize the connection
+  </message>
+  <message name="IDS_PAIRING_HOST_CONNECTION_ERROR_TITLE" desc="Title of the host's connection error page during the bootstrapping process or 'Chromebox for meeting' setup process.">
+    Connection was lost
   </message>
 
   <!-- Strings for the le OAuth-based enterprise enrollment page -->
   <message name="IDS_ENTERPRISE_ENROLLMENT_STATUS_REGISTRATION_FAILED" desc="Error message shown on the enrollment screen upon failed device registration.">
     Error when registering the device with the server: <ph name="CLIENT_ERROR">$1<ex>Failed to connect to the server</ex></ph>.
   </message>
   <message name="IDS_ENTERPRISE_ENROLLMENT_STATUS_NO_STATE_KEYS" desc="Error message shown on the enrollment screen when the system failed to determine server-backed state keys.">
     Oops!  The system failed to determine device identifiers for this device.
   </message>
   <message name="IDS_ENTERPRISE_ENROLLMENT_STATUS_REGISTRATION_BAD_MODE" desc="Error message shown on the enrollment screen upon receiving a bad mode on device registration.">
@@ skipping 379 matching lines @@
     Installing
   </message>
   <message name="IDS_FLAGS_PRINTER_PROVIDER_SEARCH_APP_NAME" desc="Name of the flag used to enable launching Chrome Web Store Gallery widget app for searching for printer provider apps.">
     Chrome Web Store Gallery app for printer drivers
   </message>
   <message name="IDS_FLAGS_PRINTER_PROVIDER_SEARCH_APP_DESCRIPTION" desc="Description of a flag in chrome://flags that enables launching Chrome Web Store Gallery widget app for searching for printer provider apps.">
     Enables Chrome Web Store Gallery app for printer drivers. The app searches Chrome Web Store for extensions that support printing to a USB printer with specific USB ID.
   </message>
 
 </grit-part>