Hi,
I’m afraid this has nothing to do with the plugin, but your service provider. Request limiting will not solve any real DDOS issues, for that firewalls should be used instead. I have not heard of this type of anti DDOS measures in a long time. Request limiting is usually used for shared host servers, where the host tries to save some resources on the server side, when multiple clients are shared across the same server. It works for DDOS as well of course, but it can not distinguish between “good” and “bad” requests.
The plugin does not do any requests, other than when you make a search query – it can’t, it has to be triggered by a client (ie. user with a browser).
The only way to resolve this is by lifting the rate limits (or at least increasing it), as this is going to be least of your issues. When users start to navigate across your page, they could very quicly exhaust the rate limit, then this error is going to be presented to them.
See, when I navigated a few times, I was able to get the message already: https://i.imgur.com/x1aZK7r.png
Increasing the rate limit 10x may resolve this for a single user, but will not help in cases where multiple clients have the same IP addresses by any chance.