fix https://github.com/acmesh-official/acme.sh/issues/4680

zerossl returns retry-after header within "200 OK" code.
so we don't check the "503" code anymore.

acme.sh

@@ -2222,40 +2222,40 @@ _send_signed_request() {
 
     _CACHED_NONCE="$(echo "$responseHeaders" | grep -i "Replay-Nonce:" | _head_n 1 | tr -d "\r\n " | cut -d ':' -f 2 | cut -d , -f 1)"
 
-    if ! _startswith "$code" "2"; then
-      _body="$response"
-      if [ "$needbase64" ]; then
-        _body="$(echo "$_body" | _dbase64 multiline)"
-        _debug3 _body "$_body"
-      fi
-
-      _retryafter=$(echo "$responseHeaders" | grep -i "^Retry-After *: *[0-9]\+ *" | cut -d : -f 2 | tr -d ' ' | tr -d '\r')
-      if [ "$code" = '503' ]; then
-        _sleep_overload_retry_sec=$_retryafter
-        if [ -z "$_sleep_overload_retry_sec" ]; then
-          _sleep_overload_retry_sec=5
-        fi
-        if [ $_sleep_overload_retry_sec -le 600 ]; then
-          _info "It seems the CA server is currently overloaded, let's wait and retry. Sleeping $_sleep_overload_retry_sec seconds."
-          _sleep $_sleep_overload_retry_sec
-          continue
-        else
-          _info "The retryafter=$_retryafter is too large > 600, not retry anymore."
-        fi
-      fi
-      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. Sleeping $_sleep_retry_sec seconds."
-        _CACHED_NONCE=""
-        _sleep $_sleep_retry_sec
-        continue
+    _body="$response"
+    if [ "$needbase64" ]; then
+    _body="$(echo "$_body" | _dbase64 multiline)"
+    _debug3 _body "$_body"
+    fi
+    _retryafter=$(echo "$responseHeaders" | grep -i "^Retry-After *: *[0-9]\+ *" | cut -d : -f 2 | tr -d ' ' | tr -d '\r')
+
+    if [ "$code" = '503' ] || [ "$_retryafter" ]; then
+      _sleep_overload_retry_sec=$_retryafter
+      if [ -z "$_sleep_overload_retry_sec" ]; then
+        _sleep_overload_retry_sec=5
       fi
-      if _contains "$_body" "The Replay Nonce is not recognized"; then
-        _info "The replay Nonce is not valid, let's get a new one, Sleeping $_sleep_retry_sec seconds."
-        _CACHED_NONCE=""
-        _sleep $_sleep_retry_sec
+      if [ $_sleep_overload_retry_sec -le 600 ]; then
+        _info "It seems the CA server is currently overloaded, let's wait and retry. Sleeping $_sleep_overload_retry_sec seconds."
+        _sleep $_sleep_overload_retry_sec
         continue
+      else
+        _info "The retryafter=$_retryafter is too large > 600, not retry anymore."
+        return 1
       fi
     fi
+    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. Sleeping $_sleep_retry_sec seconds."
+      _CACHED_NONCE=""
+      _sleep $_sleep_retry_sec
+      continue
+    fi
+    if _contains "$_body" "The Replay Nonce is not recognized"; then
+      _info "The replay Nonce is not valid, let's get a new one, Sleeping $_sleep_retry_sec seconds."
+      _CACHED_NONCE=""
+      _sleep $_sleep_retry_sec
+      continue
+    fi
+
     return 0
   done
   _info "Giving up sending to CA server after $MAX_REQUEST_RETRY_TIMES retries."