The error message "508 Resource Limit Is Reached" appears when your account is constantly exceeding the resources assigned to it - these can include CPU usage, RAM usage and/or the number of concurrent processes running under your account.
We run the CloudLinux operating system on servers to better resource manage , and this allows us to isolate accounts in their own lightweight virtual environment with exact amount of resources allocated to each account. If you have resource heavy sites on your account then it's possible you are constantly reaching these limits and your account is being temporarily throttled to maintain server stability.
A resource usage spike every now and again is nothing to worry about and will cause minimum (if any) disruption to your account, but if you are facing constant issues then you should be looking at optimizing the code on your websites to use minimum resources, or upgrading to a VPS or dedicated server.
