diff --git a/app/src/main/java/eu/faircode/email/EntityIdentity.java b/app/src/main/java/eu/faircode/email/EntityIdentity.java
index 12d2dc7836..5a6ba03d0b 100644
--- a/app/src/main/java/eu/faircode/email/EntityIdentity.java
+++ b/app/src/main/java/eu/faircode/email/EntityIdentity.java
@@ -166,7 +166,7 @@ public class EntityIdentity {
             if (user.equalsIgnoreCase(cemail[0]))
                 return true;
         } else {
-            String input = (sender_extra_regex.contains("@") ? other : cother[0]);
+            String input = (sender_extra_regex.contains("@") ? other.toLowerCase() : cother[0]);
             if (Pattern.matches(sender_extra_regex, input))
                 return true;
         }