diff --git a/auth-pam.c b/auth-pam.c
index d2b3c3483..29607e041 100644
--- a/auth-pam.c
+++ b/auth-pam.c
@@ -474,6 +474,7 @@ check_pam_user(Authctxt *authctxt)
 	if (strcmp(sshpam_initial_user, pam_user) != 0) {
 		error_f("PAM user \"%s\" does not match previous \"%s\"",
 		      pam_user, sshpam_initial_user);
+		return PAM_USER_UNKNOWN;
 	}
 	return PAM_SUCCESS;
 }