diff --git a/src/yunohost/certificate.py b/src/yunohost/certificate.py
index bd7d02962..24a41b572 100644
--- a/src/yunohost/certificate.py
+++ b/src/yunohost/certificate.py
@@ -444,7 +444,7 @@ investigate :
 
 """ % (domain, exception_message, stack, logs)
 
-    message = """
+    message = """\
 From: %s
 To: %s
 Subject: %s