Special page to handle 500 errors

BTCPayServer/Controllers/ErrorController.cs

@@ -14,7 +14,8 @@ namespace BTCPayServer.Controllers
         {
             if (statusCode.HasValue)
             {
-                if (statusCode.Value == 404)
+                var specialPages = new[] { 404, 500 };
+                if (specialPages.Any(a => a == statusCode.Value))
                 {
                     var viewName = statusCode.ToString();
                     return View(viewName);

BTCPayServer/Views/Error/500.cshtml

@@ -0,0 +1,15 @@
+@{
+    ViewData["ErrorTitle"] = "500 - Internal Server Error";
+}
+
+<p class="lead-login">
+    Whoops, something really went wrong! <a href="https://twitter.com/mrkukks">Mr Kukks</a> is so sorry.
+    <br /><br />
+    <a href="https://twitter.com/mrkukks" target="_blank">
+        <img src="~/img/errorpages/500_mrkukks.jpg" alt="Mr Kukks puppy eyes" title="The most innocent look you'll ever see" />
+    </a>
+    <br /><br />
+    Consult server log and consider submitting issue on BTCPayServer GitHub.
+    <br /><br />
+    <a href="/">Navigate back to home</a>.
+</p>