diff -r f927ef81a12b -r 0e3f275b2492 src/server/webdav/webdav.c
--- a/src/server/webdav/webdav.c	Tue Apr 19 18:23:54 2022 +0200
+++ b/src/server/webdav/webdav.c	Tue Apr 19 18:34:40 2022 +0200
@@ -70,6 +70,7 @@
     default_backend.opt_mkcol = NULL;
     default_backend.opt_delete = NULL;
     default_backend.settings = WS_WEBDAV_PROPFIND_USE_VFS;
+    default_backend.instance = NULL;
 }
 
 int webdav_init(pblock *pb, Session *sn, Request *rq) {