On our shared hosting (Helium / Carbon / Titanium plans) we use rate limiting to prevent too many dynamic calls to PHP processes. This allows us to ensure everyone gets a fair use of the server, and no one user can effectively use all the server resources to the detriment of other clients.Too many dynamic processes from one site will necessarily impact the performance of other sites. This rate limiting kicks in at a fairly high rate (exceeding 2 hits per second allowing for a burst of 60 hits without limiting every 10 minutes).
We strongly encourage the use of caching plugins for web applications (such as WP Rocket or WP Super Cache for WordPress) to reduce the number of dynamic requests your website will make. Some plugins require dynamic processing to run some of their core functions - such as any tool that has a mini-cart or other dynamic element for a WooCommerce website. These sorts of tools are generally fine, but will increase dynamic processing (and also slow down the user experience slightly). We also have a guide on how to reduce the dynamic requests your WordPress site makes.
If you have just activated a plugin, or used a plugin, when you received this error we would recommend contacting the plugin developer to ask them about rate limiting their own code. A number of plugins do this automatically - or allow you to control the rate at which they do it. Examples would be most backup plugins, WP All Import / All Export, and more. Doing so really should be standard behaviour for any plugin that needs to make a significant number of dynamic requests.
If you need help identifying the cause of your dynamic processes and have already checked the logs, reach out to us and we'll do our best to help.
