From bb352b546b5610be97f1d688b9cd9c52c56c2d0c Mon Sep 17 00:00:00 2001
From: Hasan Berk KARABAY
 <85685449+Heisenberk-Karabay@users.noreply.github.com>
Date: Fri, 16 May 2025 16:56:21 +0300
Subject: [PATCH 1/3] Editor: Skip CesiumIonSession.Tick() when Unity is
 offline

Problem
-------
If the Unity Editor launches without an Internet connection,
CesiumIonServerManager.instance.currentSession.Tick() throws every
frame because the DNS lookup for https://api.cesium.com fails.
The result is an endless stream of red-error messages:

    Exception: Request for `https://api.cesium.com/appData` failed:
    Cannot resolve destination host
    Exception: Failed to obtain _appData, can't resume connection

The spam clutters the Console and can even interrupt later domain
reloads.

Change
------
Added a single guard clause at the top of
Editor/CesiumEditorUtility.UpdateIonSession():

    if (Application.internetReachability == NetworkReachability.NotReachable)
        return;

When Unity reports that the machine is offline the function now returns
immediately, so the session is ticked again only after connectivity is
restored.
---
 Editor/CesiumEditorUtility.cs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Editor/CesiumEditorUtility.cs b/Editor/CesiumEditorUtility.cs
index f6edd7fb..67c95936 100644
--- a/Editor/CesiumEditorUtility.cs
+++ b/Editor/CesiumEditorUtility.cs
@@ -21,6 +21,8 @@ static CesiumEditorUtility()
 
         static void UpdateIonSession()
         {
+            if (Application.internetReachability == NetworkReachability.NotReachable)
+                return;
             try
             {
                 CesiumIonServerManager.instance.currentSession.Tick();

From dca9002dab5de1a81dc77ffc1db69af3191dbac6 Mon Sep 17 00:00:00 2001
From: Hasan Berk KARABAY
 <85685449+Heisenberk-Karabay@users.noreply.github.com>
Date: Wed, 28 May 2025 10:46:34 +0300
Subject: [PATCH 2/3] comprehensive network-reachability check

---
 Editor/CesiumEditorUtility.cs | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/Editor/CesiumEditorUtility.cs b/Editor/CesiumEditorUtility.cs
index 67c95936..78f8eff5 100644
--- a/Editor/CesiumEditorUtility.cs
+++ b/Editor/CesiumEditorUtility.cs
@@ -21,7 +21,7 @@ static CesiumEditorUtility()
 
         static void UpdateIonSession()
         {
-            if (Application.internetReachability == NetworkReachability.NotReachable)
+            if (!IsNetworkReachable())
                 return;
             try
             {
@@ -36,6 +36,28 @@ static void UpdateIonSession()
             }
         }
 
+        private static bool IsNetworkReachable()
+        {
+            switch (Application.internetReachability)
+            {
+                case NetworkReachability.ReachableViaCarrierDataNetwork:
+                    // Reachable via carrier data network
+                    return true;
+
+                case NetworkReachability.ReachableViaLocalAreaNetwork:
+                    // Reachable via Local Area Network.
+                    return true;
+
+                case NetworkReachability.NotReachable:
+                    // Not Reachable.
+                    return false;
+
+                default:
+                    // Not Reachable.
+                    return false;
+            }
+        }
+
         static void
         HandleCesium3DTilesetLoadFailure(Cesium3DTilesetLoadFailureDetails details)
         {

From de9939ac8fb2c6f33c89586bda4f6d5831de103c Mon Sep 17 00:00:00 2001
From: Hasan Berk KARABAY
 <85685449+Heisenberk-Karabay@users.noreply.github.com>
Date: Thu, 29 May 2025 09:59:44 +0300
Subject: [PATCH 3/3] Update CHANGES.md

---
 CHANGES.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index fd7d92c9..31123b11 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,12 @@
 # Change Log
 
+## ? - ?
+
+##### Additions :tada:
+
+##### Fixes :wrench:
+- Fixed a bug related to using offline tilesets without internet connection.
+  
 ## v1.16.0 - 2025-05-01
 
 ##### Additions :tada: