diff --git a/pam_yubico.c b/pam_yubico.c
index bf1b55f..c010678 100644
--- a/pam_yubico.c
+++ b/pam_yubico.c
@@ -637,6 +637,7 @@ do_challenge_response(pam_handle_t *pamh, struct cfg *cfg, const char *username)
   DBG(("Challenge-response success!"));
   errstr = NULL;
   errno = 0;
+  yk_errno = 0;
 
 restpriv_out:
   if (!cfg->chalresp_path) {