diff --git a/lisp/auth-source.el b/lisp/auth-source.el
index b7a7b41..d0ca4a2 100644
--- a/lisp/auth-source.el
+++ b/lisp/auth-source.el
@@ -333,7 +333,10 @@ If the value is not a list, symmetric encryption will be used."
 Using the plist ENTRY, get the :host, :protocol, and :user search
 parameters.  Accepts :port as an alias to :protocol.  Sets all
 the parameters to t if they are missing."
-  (let (val)
+  (let ((entry (if (stringp entry)
+                   nil
+                 entry))
+        val)
     (when (setq val (plist-get entry :host))
       (oset backend host val))
     (when (setq val (plist-get entry :user))