diff --git a/app/src/main/java/eu/faircode/email/Core.java b/app/src/main/java/eu/faircode/email/Core.java
index 74b6eb223c..4aa64e538a 100644
--- a/app/src/main/java/eu/faircode/email/Core.java
+++ b/app/src/main/java/eu/faircode/email/Core.java
@@ -1992,7 +1992,7 @@ class Core {
         boolean plain_text = jargs.optBoolean(0);
         String charset = jargs.optString(1, null);
 
-        if (message.uid != null)
+        if (message.uid == null)
             throw new IllegalArgumentException("uid missing");
 
         // Download message body