diff --git a/Release/include/cpprest/http_msg.h b/Release/include/cpprest/http_msg.h
index a2477fd34d..50f05ef213 100644
--- a/Release/include/cpprest/http_msg.h
+++ b/Release/include/cpprest/http_msg.h
@@ -248,6 +248,28 @@ class http_exception : public std::exception
         m_msg = m_errorCode.message();
     }
 
+    /// <summary>
+    /// Creates an <c>http_exception</c> with from a error code with a category, and a string message.
+    /// </summary>
+    /// <param name="errorCode">Error code value.</param>
+    /// <param name="whatArg">Error message string.</param>
+    http_exception(std::error_code errorCode, const utility::string_t& whatArg)
+        : m_errorCode(std::move(errorCode)), m_msg(utility::conversions::to_utf8string(whatArg))
+    {
+    }
+
+#ifdef _WIN32
+    /// <summary>
+    /// Creates an <c>http_exception</c> with from a error code with a category, and a string message.
+    /// </summary>
+    /// <param name="errorCode">Error code value.</param>
+    /// <param name="whatArg">Error message string.</param>
+    http_exception(std::error_code errorCode, std::string whatArg)
+        : m_errorCode(std::move(errorCode)), m_msg(std::move(whatArg))
+    {
+    }
+#endif
+
     /// <summary>
     /// Gets a string identifying the cause of the exception.
     /// </summary>
diff --git a/Release/src/http/client/http_client_asio.cpp b/Release/src/http/client/http_client_asio.cpp
index 3a5f82800c..1df332d617 100644
--- a/Release/src/http/client/http_client_asio.cpp
+++ b/Release/src/http/client/http_client_asio.cpp
@@ -87,12 +87,11 @@ namespace
 {
 const std::string CRLF("\r\n");
 
-std::string calc_cn_host(const bool secure,
-                         const web::http::uri& baseUri,
+std::string calc_cn_host(const web::http::uri& baseUri,
                          const web::http::http_headers& requestHeaders)
 {
     std::string result;
-    if (secure)
+    if (baseUri.scheme() == U("https"))
     {
         const utility::string_t* encResult;
         const auto hostHeader = requestHeaders.find(_XPLATSTR("Host"));
@@ -472,7 +471,6 @@ class asio_client final : public _http_client_communicator
         : _http_client_communicator(std::move(address), std::move(client_config))
         , m_resolver(crossplat::threadpool::shared_instance().service())
         , m_pool(std::make_shared<asio_connection_pool>())
-        , m_start_with_ssl(base_uri().scheme() == U("https") && !this->client_config().proxy().is_specified())
     {
     }
 
@@ -482,13 +480,13 @@ class asio_client final : public _http_client_communicator
 
     std::shared_ptr<asio_connection> obtain_connection(const http_request& req)
     {
-        std::string cn_host = calc_cn_host(m_start_with_ssl, base_uri(), req.headers());
+        std::string cn_host = calc_cn_host(base_uri(), req.headers());
         std::shared_ptr<asio_connection> conn = m_pool->try_acquire(cn_host);
         if (conn == nullptr)
         {
             // Pool was empty. Create a new connection
             conn = std::make_shared<asio_connection>(crossplat::threadpool::shared_instance().service());
-            if (m_start_with_ssl)
+            if (base_uri().scheme() == U("https") && !this->client_config().proxy().is_specified())
             {
                 conn->upgrade_to_ssl(std::move(cn_host), this->client_config().get_ssl_context_callback());
             }
@@ -499,13 +497,10 @@ class asio_client final : public _http_client_communicator
 
     virtual pplx::task<http_response> propagate(http_request request) override;
 
-    bool start_with_ssl() const CPPREST_NOEXCEPT { return m_start_with_ssl; }
-
     tcp::resolver m_resolver;
 
 private:
     const std::shared_ptr<asio_connection_pool> m_pool;
-    const bool m_start_with_ssl;
 };
 
 class asio_context final : public request_context, public std::enable_shared_from_this<asio_context>
@@ -631,7 +626,15 @@ class asio_context final : public request_context, public std::enable_shared_fro
                 m_context->m_timer.reset();
                 //// Replace the connection. This causes old connection object to go out of scope.
                 auto client = std::static_pointer_cast<asio_client>(m_context->m_http_client);
-                m_context->m_connection = client->obtain_connection(m_context->m_request);
+                try
+                {
+                    m_context->m_connection = client->obtain_connection(m_context->m_request);
+                }
+                catch (...)
+                {
+                    m_context->report_exception(std::current_exception());
+                    return;
+                }
 
                 auto endpoint = *endpoints;
                 m_context->m_connection->async_connect(endpoint,
@@ -688,7 +691,15 @@ class asio_context final : public request_context, public std::enable_shared_fro
                     return;
                 }
 
-                m_context->upgrade_to_ssl();
+                try
+                {
+                    m_context->upgrade_to_ssl();
+                }
+                catch (...)
+                {
+                    m_context->report_exception(std::current_exception());
+                    return;
+                }
 
                 m_ssl_tunnel_established(m_context);
             }
@@ -925,7 +936,7 @@ class asio_context final : public request_context, public std::enable_shared_fro
     void upgrade_to_ssl()
     {
         auto& client = static_cast<asio_client&>(*m_http_client);
-        m_connection->upgrade_to_ssl(calc_cn_host(client.start_with_ssl(), client.base_uri(), m_request.headers()),
+        m_connection->upgrade_to_ssl(calc_cn_host(client.base_uri(), m_request.headers()),
                                      client.client_config().get_ssl_context_callback());
     }
 
@@ -1009,7 +1020,15 @@ class asio_context final : public request_context, public std::enable_shared_fro
         {
             // Replace the connection. This causes old connection object to go out of scope.
             auto client = std::static_pointer_cast<asio_client>(m_http_client);
-            m_connection = client->obtain_connection(m_request);
+            try
+            {
+                m_connection = client->obtain_connection(m_request);
+            }
+            catch (...)
+            {
+                request_context::report_exception(std::current_exception());
+                return;
+            }
 
             auto endpoint = *endpoints;
             m_connection->async_connect(
@@ -1330,7 +1349,16 @@ class asio_context final : public request_context, public std::enable_shared_fro
             // Create a new context and copy the request object, completion event and
             // cancellation registration to maintain the old state.
             // This also obtains a new connection from pool.
-            auto new_ctx = create_request_context(m_http_client, m_request);
+            std::shared_ptr<request_context> new_ctx;
+            try
+            {
+                new_ctx = create_request_context(m_http_client, m_request);
+            }
+            catch (...)
+            {
+                report_exception(std::current_exception());
+                return;
+            }
 
             // If the request contains a valid instream, we try to rewind it to
             // replay the just-failed request. Otherwise we assume that no data
@@ -1940,7 +1968,15 @@ void asio_client::send_request(const std::shared_ptr<request_context>& request_c
 pplx::task<http_response> asio_client::propagate(http_request request)
 {
     auto self = std::static_pointer_cast<_http_client_communicator>(shared_from_this());
-    auto context = details::asio_context::create_request_context(self, request);
+    std::shared_ptr<request_context> context;
+    try
+    {
+        context = details::asio_context::create_request_context(self, request);
+    }
+    catch (...)
+    {
+        return pplx::task_from_exception<http_response>(std::current_exception());
+    }
 
     // Use a task to externally signal the final result and completion of the task.
     auto result_task = pplx::create_task(context->m_request_completion);