It seems your hosting provider is using a single account for their Let's Encrypt activities, as the "too many new orders recently" error corresponds with the " maximum of 300 New Orders per account per 3 hours" rate limit from the linked page in the error you've pasted.
However there might be some issue at your hosting provider. For example, a loop requesting orders very often for a hostname which is failing. So I would like to suggest for you to contact your hosting provider with your current problem. It's probably something only they can fix or make better.
On the other hand, you might get lucky if you try often enough, as the rate limit only has a three hour window. If you fail again and again, it might mean something is wrong at your hosting provider as I stated above.