diff --git a/acme.sh b/acme.sh
index b0c30f44..7bfc88ef 100755
--- a/acme.sh
+++ b/acme.sh
@@ -3692,7 +3692,7 @@ $_authorizations_map"
       fi
 
       if [ "$ACME_VERSION" = "2" ]; then
-        response="$(echo "$_authorizations_map" | grep "^${d//./\.}," | sed "s/$d,//")"
+        response="$(echo "$_authorizations_map" | grep "^${d//./\\.}," | sed "s/$d,//")"
         _debug2 "response" "$response"
         if [ -z "$response" ]; then
           _err "get to authz error."