diff --git a/EnotaryoPH/EnotaryoPH.Web/Common/Extensions/StringExtensions.cs b/EnotaryoPH/EnotaryoPH.Web/Common/Extensions/StringExtensions.cs
index 391a55d..deacccc 100644
--- a/EnotaryoPH/EnotaryoPH.Web/Common/Extensions/StringExtensions.cs
+++ b/EnotaryoPH/EnotaryoPH.Web/Common/Extensions/StringExtensions.cs
@@ -10,6 +10,8 @@
 
         public static bool IsInList(this string s, params string[] list) => list.Contains(s, StringComparer.OrdinalIgnoreCase);
 
+        public static bool IsInList<T>(this string stringValue, IEnumerable<T> listOfEnums) where T : struct, Enum => Enum.TryParse(stringValue, out T enumValue) && listOfEnums.Contains(enumValue);
+
         public static string NullIfWhiteSpace(this string s) => string.IsNullOrWhiteSpace(s) ? null : s;
 
         public static Guid ToGuidFromBase64(this string s)
diff --git a/EnotaryoPH/EnotaryoPH.Web/Pages/Participant/Registration/Index.cshtml.cs b/EnotaryoPH/EnotaryoPH.Web/Pages/Participant/Registration/Index.cshtml.cs
index a51bc9e..d3d1596 100644
--- a/EnotaryoPH/EnotaryoPH.Web/Pages/Participant/Registration/Index.cshtml.cs
+++ b/EnotaryoPH/EnotaryoPH.Web/Pages/Participant/Registration/Index.cshtml.cs
@@ -24,16 +24,17 @@ namespace EnotaryoPH.Web.Pages.Participant.Registration
                 return NotFound();
             }
 
+            var validStates = new SignatoryStatus[] { SignatoryStatus.New, SignatoryStatus.Registered, SignatoryStatus.EmailSent };
             var invitationCodeGuid = InvitationCode.ToGuidFromBase64();
             var signatory = _notaryoDBContext.TransactionSignatories
                 .Include(e => e.Transaction)
-                .FirstOrDefault(e => e.InvitationCode == invitationCodeGuid.ToString() && (e.Status == nameof(SignatoryStatus.New) || e.Status == nameof(SignatoryStatus.Registered)));
-            if (signatory == null)
+                .FirstOrDefault(e => e.InvitationCode == invitationCodeGuid.ToString());
+            if (signatory == null || !signatory.Status.IsInList(validStates))
             {
                 return NotFound();
             }
 
-            var existingUser = _notaryoDBContext.Users.FirstOrDefault(e => e.Email.Equals(signatory.Email, StringComparison.CurrentCultureIgnoreCase));
+            var existingUser = _notaryoDBContext.Users.FirstOrDefault(e => e.Email.ToLower() == signatory.Email.ToLower());
             if (existingUser != null)
             {
                 signatory.Status = nameof(SignatoryStatus.Registered);