diff --git a/QuickFIXn/Transport/SocketInitiator.cs b/QuickFIXn/Transport/SocketInitiator.cs
old mode 100755
new mode 100644
index a150dc69a..96e848a09
--- a/QuickFIXn/Transport/SocketInitiator.cs
+++ b/QuickFIXn/Transport/SocketInitiator.cs
@@ -1,13 +1,14 @@
 #nullable enable
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
-using System.Net.Sockets;
 using System.Net;
+using System.Net.Sockets;
 using System.Threading;
-using System.IO;
 using QuickFix.Logger;
 using QuickFix.Store;
+using QuickFix.Util;
 
 namespace QuickFix.Transport
 {
@@ -73,7 +74,7 @@ public static void SocketInitiatorThreadStart(object socketInitiatorThread)
                 }
                 catch (System.Security.Authentication.AuthenticationException ex) // some certificate problems
                 {
-                    exceptionEvent = $"Connection failed (AuthenticationException): {ex.Message}";
+                    exceptionEvent = $"Connection failed (AuthenticationException): {ex.GetFullMessage()}";
                 }
                 catch (Exception ex)
                 {
diff --git a/QuickFIXn/Transport/StreamFactory.cs b/QuickFIXn/Transport/StreamFactory.cs
index d369fbcf6..3e00887c9 100644
--- a/QuickFIXn/Transport/StreamFactory.cs
+++ b/QuickFIXn/Transport/StreamFactory.cs
@@ -1,15 +1,16 @@
 #nullable enable
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
+using System.Diagnostics;
 using System.IO;
+using System.Linq;
+using System.Net;
+using System.Net.Security;
 using System.Net.Sockets;
+using System.Text;
 using System.Security.Cryptography.X509Certificates;
-using System.Net.Security;
-using System.Diagnostics;
-using System.Net;
 using QuickFix.Logger;
+using QuickFix.Util;
 
 namespace QuickFix.Transport
 {
@@ -271,7 +272,7 @@ public Stream CreateClientStreamAndAuthenticate(Stream innerStream)
                 }
                 catch (System.Security.Authentication.AuthenticationException ex)
                 {
-                    _log.OnEvent("Unable to perform authentication against server: " + ex.Message);
+                    _log.OnEvent("Unable to perform authentication against server: " + ex.GetFullMessage());
                     throw;
                 }
 
@@ -312,7 +313,7 @@ public Stream CreateServerStreamAndAuthenticate(Stream innerStream)
                 }
                 catch (System.Security.Authentication.AuthenticationException ex)
                 {
-                    _log.OnEvent("Unable to perform authentication against server: " + ex.Message);
+                    _log.OnEvent("Unable to perform authentication against server: " + ex.GetFullMessage());
                     throw;
                 }
 
diff --git a/QuickFIXn/Util/ExceptionExtensions.cs b/QuickFIXn/Util/ExceptionExtensions.cs
new file mode 100644
index 000000000..18e623ba4
--- /dev/null
+++ b/QuickFIXn/Util/ExceptionExtensions.cs
@@ -0,0 +1,14 @@
+using System;
+
+namespace QuickFix.Util
+{
+    internal static class ExceptionExtensions
+    {
+        public static string GetFullMessage(this Exception ex)
+        {
+            return ex.InnerException == null
+                ? ex.Message
+                : ex.Message + " --> " + ex.InnerException.GetFullMessage();
+        }
+    }
+}
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 07410c44d..c408633a9 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -64,6 +64,7 @@ What's New
 * #823 - get rid of IOIQty enums in FIX5 DDs, allow free string (gbirchmeier)
 * #786 - rewrite HttpServer: better HTML, no crash on errors (gbirchmeier)
 * #697 - new SocketIgnoreProxy setting (ABSJ415)
+* #740 - Capture inner exception messages when handling authentication exceptions (rars)
 
 ### v1.11.2:
 * same as v1.11.1, but I fixed the readme in the pushed nuget packages
diff --git a/UnitTests/Util/ExceptionExtensionsTests.cs b/UnitTests/Util/ExceptionExtensionsTests.cs
new file mode 100644
index 000000000..1cbda5607
--- /dev/null
+++ b/UnitTests/Util/ExceptionExtensionsTests.cs
@@ -0,0 +1,29 @@
+using System;
+using NUnit.Framework;
+using QuickFix.Util;
+
+namespace UnitTests.Util
+{
+    public sealed class ExceptionExtensionsTests
+    {
+        [Test]
+        public void WhenInnerExceptionShouldReturnJoinedInnerExceptionMessages()
+        {
+            var exception = new Exception(
+                "Outer exception, see inner exception",
+                new Exception("My inner exception message"));
+
+            Assert.AreEqual(
+                exception.GetFullMessage(),
+                "Outer exception, see inner exception --> My inner exception message");
+        }
+
+        [Test]
+        public void WhenNoInnerExceptionShouldReturnExceptionMessageUnmodified()
+        {
+            var exception = new Exception("My exception message");
+
+            Assert.AreEqual(exception.GetFullMessage(), "My exception message");
+        }
+    }
+}