diff --git a/acme.sh b/acme.sh
index 8fd321b..43b3f63 100755
--- a/acme.sh
+++ b/acme.sh
@@ -1899,6 +1899,7 @@ _send_signed_request() {
 
     if _contains "$_body" "JWS has invalid anti-replay nonce" || _contains "$_body" "JWS has an invalid anti-replay nonce"; then
       _info "It seems the CA server is busy now, let's wait and retry."
+      _CACHED_NONCE=""
       _sleep 5
       continue
     fi