diff --git a/files/cert2json.py b/files/cert2json.py
index b17f656711f59cec0512b1da91048f2f6082e060..177210c12bc3ba871e24261458628d2a058b7173 100755
--- a/files/cert2json.py
+++ b/files/cert2json.py
@@ -35,7 +35,7 @@ JSON_FILE = "/etc/acme/{}.json".format(PROVIDER)
 
 
 with open(YAML_FILE, "w") as yaml_out:
-    yaml_out.write("---\n".format(PROVIDER_STRING))
+    yaml_out.write("---\n")
     for txt_line in DECODED_OUTPUT:
         if "Certificate Name:" in txt_line:
             txt_line_out = re.sub('.*Certificate Name: ', '  ', txt_line) + ":"