diff --git a/Tests/WalletConnectSharp.Sign.Test/SignTests.cs b/Tests/WalletConnectSharp.Sign.Test/SignTests.cs
index d7d005b..55d136a 100644
--- a/Tests/WalletConnectSharp.Sign.Test/SignTests.cs
+++ b/Tests/WalletConnectSharp.Sign.Test/SignTests.cs
@@ -1,11 +1,9 @@
 using WalletConnectSharp.Common.Model.Errors;
 using WalletConnectSharp.Common.Utils;
-using WalletConnectSharp.Crypto;
 using WalletConnectSharp.Network.Models;
 using WalletConnectSharp.Sign.Interfaces;
 using WalletConnectSharp.Sign.Models;
 using WalletConnectSharp.Sign.Models.Engine;
-using WalletConnectSharp.Storage;
 using WalletConnectSharp.Tests.Common;
 using Xunit;
 using Xunit.Abstractions;
@@ -786,8 +784,8 @@ public async Task TestAddressProviderChainIdChange()
 
             _ = await TestConnectMethod(ClientA, ClientB);
 
-            const string badChainId = "invalid:invalid";
-            await Assert.ThrowsAsync<InvalidOperationException>(() => ClientA.AddressProvider.SetDefaultChainIdAsync(badChainId));
+            const string badChainId = "badChainId";
+            await Assert.ThrowsAsync<ArgumentException>(() => ClientA.AddressProvider.SetDefaultChainIdAsync(badChainId));
 
             // Change the default chain id
             const string newChainId = "eip155:10";
diff --git a/WalletConnectSharp.Sign/Controllers/AddressProvider.cs b/WalletConnectSharp.Sign/Controllers/AddressProvider.cs
index 683ec76..8fa7e1a 100644
--- a/WalletConnectSharp.Sign/Controllers/AddressProvider.cs
+++ b/WalletConnectSharp.Sign/Controllers/AddressProvider.cs
@@ -1,4 +1,5 @@
 using WalletConnectSharp.Common.Utils;
+using WalletConnectSharp.Core;
 using WalletConnectSharp.Sign.Interfaces;
 using WalletConnectSharp.Sign.Models;
 using WalletConnectSharp.Sign.Models.Engine.Events;
@@ -220,9 +221,9 @@ public async Task SetDefaultChainIdAsync(string chainId)
             throw new ArgumentNullException(nameof(chainId));
         }
 
-        if (!DefaultSession.Namespaces[DefaultNamespace].Chains.Contains(chainId))
+        if (!Utils.IsValidChainId(chainId))
         {
-            throw new InvalidOperationException($"Chain {chainId} is not available in the current session");
+            throw new ArgumentException("The format of 'chainId' is invalid. Must be in the format of 'namespace:chainId' (e.g. 'eip155:10'). See CAIP-2 for more information.");
         }
 
         DefaultChainId = chainId;